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diff --git a/37566.txt b/37566.txt new file mode 100644 index 0000000..6fc86a6 --- /dev/null +++ b/37566.txt @@ -0,0 +1,7230 @@ +The Project Gutenberg EBook of Natural History of the Ornate Box Turtle, +Terrapene ornata ornata Agassiz, by John M. Legler + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz + +Author: John M. Legler + +Release Date: September 29, 2011 [EBook #37566] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK NATURAL HISTORY OF THE *** + + + + +Produced by Chris Curnow, Tom Cosmas, Joseph Cooper and +the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + + + +UNIVERSITY OF KANSAS PUBLICATIONS + +MUSEUM OF NATURAL HISTORY + +Volume 11, No. 10, pp. 527-669, 16 pls., 29 figs. + +March 7, 1960 + + + + +Natural History of the Ornate Box Turtle, +Terrapene ornata ornata Agassiz + + +BY + + +JOHN M. LEGLER + + +UNIVERSITY OF KANSAS +LAWRENCE + +1960 + + + + +UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY + +Editors: E. Raymond Hall, Chairman, Henry S. Fitch, +Robert W. Wilson + + +Volume 11, No. 10, pp. 527-669, 16 pls., 29 figs. +Published March 7, 1960 + + +UNIVERSITY OF KANSAS +Lawrence, Kansas + + +PRINTED IN +THE STATE PRINTING PLANT +TOPEKA, KANSAS +1960 + +[Union Label] + +28-773 + + + + +Natural History of the Ornate Box Turtle, +Terrapene ornata ornata Agassiz + +BY + +JOHN M. LEGLER + + + + +CONTENTS + + + + PAGE + + Introduction 531 + Acknowledgments 531 + Systematic Relationships and Distribution 532 + Fossils 534 + Economic Importance 534 + Study Areas 535 + Materials and Methods 537 + Terminology 539 + + Habitat and Limiting Factors 539 + + Habitat in Kansas 542 + + Reproduction 543 + + Mating 543 + Insemination 545 + Sexual Cycle of Males 545 + Sexual Cycle of Females 549 + Nesting 554 + Eggs 558 + Embryonic Development 560 + Fertility and Prenatal Mortality 564 + Reproductive Potential 565 + Number of Reproductive Years 565 + + Growth and Development 565 + Initiation of Growth 565 + Size and Appearance at Hatching 566 + Growth of Epidermal Laminae 568 + Growth of Juveniles 575 + Growth in Later Life 578 + Annual Period of Growth 580 + Environmental Factors Influencing Growth 580 + Number of Growing Years 584 + Longevity 585 + Weight 586 + Bony Shell 586 + Color and Markings 593 + Wear 595 + + Sexual Dimorphism 595 + + Temperature Relationships 598 + Optimum Temperature 599 + Basking 600 + Toleration of Thermal Maxima and Minima 601 + + Hibernation 611 + + Diet 617 + + Populations 623 + + Movements 626 + Locomotion 627 + Daily Cycle of Activity 629 + Seasonal Cycle of Activity 630 + Home Range 632 + Homing Behavior 636 + Social Relationships 637 + + Injuries 638 + + Repair of Injuries to the Shell 641 + + Ectoparasites 643 + + Predators 646 + + Defence 648 + + Discussion of Adaptations 650 + + Summary 656 + + Literature cited 663 + + + + +INTRODUCTION + + +The ornate box turtle, _Terrapene o. ornata_ Agassiz, was studied more +or less continuously from September, 1953, until July, 1957. Intensive +field studies were made of free-living, marked populations in two +small areas of Douglas County, Kansas, in the period 1954 to 1956. +Laboratory studies were made, whenever possible, of phenomena +difficult to observe in the field, or to clarify or substantiate field +observations. Certain phases of the work (for example, studies of +populations and movements) were based almost entirely on field +observation whereas other phases (for example, growth and gametogenic +cycles) were carried out almost entirely within the laboratory on +specimens obtained from eastern Kansas and other localities. + +A taxonomic revision of the genus _Terrapene_ was begun in 1956 as an +outgrowth of the present study. The systematic status of _T. ornata_ +and other species is here discussed only briefly. + +Objectives of the study here reported on were: 1) to learn as much as +possible concerning the habits, adaptations, and life history of _T. +o. ornata_; 2) to compare the information thus acquired with +corresponding information on other emyid and testudinid chelonians, +and especially with that on other species and subspecies of +_Terrapene_; 3) to determine what factors limit the geographic +distribution of ornate box turtles; and, 4) to determine the role of +ornate box turtles in an ecological community. + + +Acknowledgments + +The aid given by a number of persons has contributed substantially to +the present study. I am grateful to my wife, Avis J. Legler, who, more +than any single person, has unselfishly contributed her time to this +project; in addition to making all the histological preparations and +typing the entire manuscript, she has assisted and encouraged me in +every phase of the study. Dr. Henry S. Fitch has been most helpful in +offering counsel and encouragement. Thanks are due Professor E. +Raymond Hall for critically reading the manuscript. + +Special thanks are due also to the following persons: Professor A. B. +Leonard for helpful suggestions dealing with photography and for +advice on several parts of the manuscript; Professor William C. Young +for the use of facilities at the Endocrine Laboratory, University of +Kansas; Professor Edward H. Taylor for permission to study specimens +in his care; Dr. Richard B. Loomis for identifying chigger mites and +offering helpful suggestions on the discussion of ectoparasites; Mr. +Irwin Ungar for identification of plants; and, Mr. William R. +Brecheisen for allowing me to examine his field notes and for +assistance with field work. Identifications of animal remains in +stomachs were made by Professor A. B. Leonard (mollusks, crustaceans), +Dr. George W. Byers (arthropods), and Dr. Sydney Anderson (mammals). + +Miss Sophia Damm generously permitted the use of her property as a +study area and Mr. Walter W. Wulfkuhle made available two saddle +horses that greatly facilitated field work. The drawings (with the +exception of Fig. 21) are by Miss Lucy Jean Remple. All photographs +are by the author. + +I am grateful also to the Kansas Academy of Science for three research +grants (totaling $175.00) that supported part of the work. The brief +discussion of taxonomic relationships and distribution results partly +from studies made by means of two research grants (totaling $150.00), +from the Graduate School, University of Kansas, for which I thank Dean +John H. Nelson. + + +Systematic Relationships and Distribution + +Turtles of the genus _Terrapene_ belong to the Emyidae, a family +comprising chiefly aquatic and semiaquatic species. _Terrapene_, +nevertheless, is adapted for terrestrial existence and differs from +all other North American emyids in having a hinged and movable +plastron and a down-turned (although often notched) maxillary beak. +_Emydoidea blandingi_, the only other North American emyid with a +hinged plastron, lacks a down-turned beak. The adaptations of box +turtles to terrestrial existence (reduction of webbing between toes, +reduction in number of phalanges, reduction of zygomatic arch, and +heightening of shell) occur in far greater degree in true land +tortoises of the family Testudinidae. Four genera of emyid turtles in +the eastern hemisphere (_Cuora_, _Cyclemys_, _Emys_, and _Notochelys_) +possess terrestrial adaptations paralleling those of _Terrapene_ but +(with the possible exception of _Cuora_) the adaptations are less +pronounced than in _Terrapene_. A movable plastron has occurred +independently in two groups of emyids in the New World and in at least +three groups in the Old World. + +The genus _Terrapene_, in my view, contains seven species, comprising +11 named kinds. Of these species, five are poorly known and occur only +in Mexico. _Terrapene mexicana_ (northeastern Mexico) and _T. +yucatana_ (Yucatan peninsula) although closely related, differ from +each other in a number of characters. Similarly, _Terrapene klauberi_ +(southern Sonora) and _T. nelsoni_ (Tepic, Nayarit--known from a +single adult male) are closely related but are considered distinct +because of their morphological differences and widely separated known +ranges. _Terrapene coahuila_, so far found only in the basin of Cuatro +CiA(C)negas in central Coahuila, is the most primitive _Terrapene_ known; +it differs from other box turtles in a number of morphological +characters and is the only member of the genus that is chiefly +aquatic. + +Two species of _Terrapene_ occur in the United States. _Terrapene +carolina_, having four recognized subspecies, has a nearly continuous +distribution from southern Maine, southern Michigan, and southern +Wisconsin, southward to Florida and the Gulf coast and westward to +southeastern Kansas, eastern Oklahoma and eastern Texas, and +characteristically inhabits wooded areas. + +_Terrapene ornata_ is a characteristic inhabitant of the western +prairies of the United States, and ranges from western and southern +Illinois, Missouri, Oklahoma, and all but the extreme eastern part of +Texas, westward to southeastern Wyoming, eastern Colorado, eastern and +southern New Mexico, and southern Arizona, and, from southern South +Dakota and southern Wisconsin, southward to northern Mexico (Fig. 1). +It is the only species of the genus that occurs in both Mexico and the +United States. The northeasternmost populations of _T. ornata_, +occurring in small areas of prairie in Indiana and Illinois, seem to +be isolated from the main range of the species. The ranges of _T. +ornata_ and _T. carolina_ overlap in the broad belt of prairie-forest +ecotone in the central United States. Interspecific matings under +laboratory conditions are not uncommon and several verbal reports of +such matings under natural conditions have reached me. Nevertheless, +after examining many specimens of both species and all alleged +"hybrids" recorded in the literature, I find no convincing evidence +that hybridization occurs under natural conditions. + +_Terrapene ornata_ differs from _T. carolina_ in having a low, +flattened carapace lacking a middorsal keel (carapace highly arched +and distinctly keeled in _carolina_), and in having four claws on the +hind foot (three or four in _carolina_), the claw of the first toe of +males being widened, thickened, and turned in (first toe not thus +modified in _carolina_). _Terrapene ornata_ is here considered to be +the most specialized member of the genus by virtue of its reduced +phalangeal formula, lightened, relatively loosely articulated shell, +reduced plastron, and lightly built skull, which completely lacks +quadratojugal bones (Fig. 2); most of these specializations seem to be +associated with adaptation for terrestrial existence in open habitats. + + [Illustration: FIG. 1. Geographic distribution of _Terrapene + ornata_. Solid symbols indicate the known range of _T. o. + ornata_ and hollow symbols the known range of _T. o. luteola_. + Half-circles show the approximate range of intergradation + between the two subspecies. Triangles indicate localities + recorded in literature; specimens were examined from all other + localities shown. Only peripheral localities are shown on the + map.] + +Two subspecies of _T. ornata_ an recognized. _Terrapene o. luteola_, +Smith and Ramsey (1952), ranges from northern Sonora (Guaymas) and +southern Arizona (southern Pima County) eastward to southeastern New +Mexico and Trans-Pecos, Texas, where it intergrades with _T. o. +ornata_; the latter subspecies is not yet known from Mexico but almost +surely occurs in the northeastern part of that country. The subspecies +_luteola_ differs from _ornata_ in being slightly larger and in having +more pale radiations on the shell (11 to 14 radiations on the second +lateral lamina in _luteola_, five to eight in _ornata_). In +individuals of _luteola_ the markings of the shell become less +distinct with advancing age and eventually are lost; shells of most +old individuals are uniform straw color or pale greenish-brown; this +change in coloration does not occur in _T. o. ornata_. + + [Illustration: FIG. 2. Dorsal and lateral views of skull of + _T. o. ornata_ (_a_ and _b_) (KU 1172, male, from 6 ml. S. + Garnett, Anderson Co., Kansas) and of _T. carolina_ + (_c_ and _d_)(KU 39742, from northern Florida). Note the + relatively higher brain-case and the incomplete zygomatic + arch in _T. o. ornata_. All figures natural size.] + + +Fossils + +Of the several species of fossil _Terrapene_ described (Hay, +1908b:359-367, Auffenberg, 1958), most are clearly allied to Recent +_T. carolina_. One species, _Terrapene longinsulae_ Hay, +(1908a:166-168, Pl. 26) from "... the Upper Miocene or Lower +Pliocene...." of Phillips County, Kansas, however, is closely related +to _T. ornata_ (if not identical). I have examined the type specimen +of _T. longinsulae_. Stock and Bode (1936:234, Pl. 8) reported _T. +ornata_ from sub-Recent deposits near Clovis, Curry County, New +Mexico. + + +Economic Importance + +Ornate box turtles, referred to as "land terrapins" or "land +tortoises" over most of the range of the species, are regarded by most +persons whom I have queried as innocuous. These turtles occasionally +damage garden crops and have been known to eat the eggs of upland game +birds. _Terrapene ornata_ is seldom used for food. A. B. Leonard told +me the species was eaten occasionally by Arapaho Indians in Dewey +County, Oklahoma. Several specimens in the University of Kansas +Archeological Collections were found in Indian middens in Rice County, +Kansas, from a culture dated approximately 1500 to 1600 A. D. The +flesh of _T. ornata_ occasionally may be toxic if the turtle has eaten +toxic fungi as has been recorded for _T. carolina_ (Carr, 1952:147). + + +Study Areas + +Preliminary studies and collections of specimens were made at a number +of localities in northeastern Kansas in 1953 and 1954. Two small areas +were finally selected for more intensive study. One of these areas, +the University of Kansas Natural History Reservation, five and +one-half miles north-northeast of Lawrence in the northeasternmost +section of Douglas County, Kansas, is a tract of 590 acres maintained +as a natural area for biological investigations. Slightly less than +two thirds (338 acres) of the Reservation is wooded; the remainder +consists of open areas having vegetation ranging from undisturbed +prairie grassland to weedy, partly brushy fields (Fitch, 1952). +Although ornate box turtles were not numerous at the Reservation, the +area was selected for study because: 1) there was a minimum of +interference there from man and none from domestic animals; 2) the +vegetation of the Reservation is typical of areas where _T. ornata_ +and _T. carolina_ occur sympatrically (actually only one specimen of +_T. carolina_ has been seen at the Reservation); and, 3) availability +of biological and climatological data there greatly facilitated the +present study. Actual field work at the Reservation consisted of +studies of hibernation and long-term observations on movements of a +few box turtles. + +A much larger number of individuals was intensively studied on a tract +of land, owned by Sophia Damm, situated 12 miles west and one and +one-half miles north of Lawrence in the northwestern quarter of +Douglas County, Kansas. The Damm Farm lies on the southern slope of a +prominence--extending northwestward from Lawrence to Topeka--that +separates the Kansas River Valley from the watershed of the Wakarusa +River to the south. The prominence has an elevation of approximately +1100 feet and is dissected on both sides by small valleys draining +into the two larger river valleys. + +The Damm Farm (see Pl. 15) has a total area of approximately 220 +acres. The crest of a hill extends diagonally from the middle of the +northern edge approximately two thirds of the distance to the +southwestern corner. Another hill is in the extreme northwestern +corner of the study area. + +The northeastern 22 acres were wooded and had small patches of +overgrazed pasture. Trees in the wooded area were Black Walnut +(_Juglans nigra_), Elms (_Ulmus americana_, _U. rubra_), Cottonwood +(_Populus deltoides_), and Northern Prickly Ash (_Xanthoxylum +americanum_). The areas used as pasture had thick growths of Buckbush +(_Symphoricarpos orbiculatus_) mixed with short grasses (_Bromus +japonicus_, _Muhlenbergia Schreberi_, and _Poa pratensis_). Farm +buildings were situated in the wooded area at the end of an entry +road. The southeastern 74 acres were cultivated; corn, wheat, and milo +were grown here and fallow fields had a sparse growth of weeds. + +Most of the western two thirds of the study area, comprising 124 +acres, was open rolling prairie (hereafter referred to as "pasture") +upon which beef-cattle were grazed (Pl. 16, Fig. 1; Pl. 17, Fig. 1; +Pl. 18, Fig. 2). Rock fences (Pl. 17, Fig. 2) two to four feet high +bordered the northern edge, southern edge, and one half of western +edge of the pasture. A wagon track lead from a gate on the entry road, +along the crest of the hill, to a gate in the southern fence. Except +for the latter gate and for ocassional under-cut places in low areas, +there were no openings in the rock fences through which box turtles +could pass. A few trees--American Elm, Hackberry (_Celtis +occidentalis_), Red Mulberry (_Morus rubra_), Osage Orange (_Maclura +pomifera_), Black Cherry (_Prunus serotina_), Box-Elder (_Acer +Negundo_), and Dogwood (_Cornus Drummondi_)--were scattered along +fences at the borders of the pasture and in ravines. Larger trees in a +small wooded creek-bed at the southwestern edge of the pasture were +chiefly Cottonwood, American Elm, Red Mulberry, and Black Willow +(_Salix nigra_). The only trees growing on the pasture itself were a +few small Osage Orange, none of which bore fruit. + +Paths were worn along fences by cattle and in several places near the +fence, usually beneath shade trees, there were large bare places where +cattle congregated. Vegetation near paths and bare places was weedy +and in some places there were tall stands of Smooth Sumac (_Rhus +glabra_). + +Rich stands of prairie grasses occurred along the top of the hill in +the pasture; bluestems (_Andropogon gerardi_, _A. scoparius_) were the +dominant species and Switchgrass (_Panicum virgatum_) and Indian grass +(_Sorghastrum nutans_) were scattered throughout. A number of small +areas on top of the hill were moderately overgrazed, as indicated by +mixture of native grasses with an association of shorter plants +consisting chiefly of Ragweed (_Ambrosia artemisiifolia_ var. +_elatior_), Mugwort (_Artemisia ludoviciana_), Japanese Chess (_Bromus +japonicus_), and Asters (_Aster_ sp.). + +The upper parts of the hillsides were overgrazed moderately to +heavily. Limestone rocks of various sizes were partly embedded in soil +or lay loose at the surface. Depressions beneath rocks provided +shelter for box turtles as well as for other small vertebrates. Native +grasses were sparse in this area and gave way to Sideoats Grama +(_Bouteloua curtipendula_), extensive patches of Smooth Sumac, and +scattered colonies of Buckbrush. + +Tall grasses were dominant on the lower hillsides and small patches of +Slough grass (_Spartina pectinata_) grew in moist areas. Ravines +originated at small intermittent springs on the sides of the hill. The +banks of ravines were high and steep and more or less bare of +vegetation. High, dense stands of Slough grass grew at intermittent +springs and along the courses of ravines; sedges (_Carex_, sp.) grew +where small pools of water formed and created marshy conditions. +Prairie grasses along the tops of ravine embankments formed a narrow +overhanging canopy of vegetation that was accentuated in many places +where the sod was under-cut by erosion or by the activities of +burrowing animals (Pl. 18, Fig. 1). Box turtles frequently sought +shelter beneath this vegetational canopy or burrowed beneath the sod. + +On the highest part of the pasture near the entry road several small +areas were nearly bare, presumably because of heavy overgrazing; +grasses (except for scattered clumps of _Bouteloua curtipendula_ and +_Setaria lutescens_) were absent and dominant vegetation consisted of +Buffalo-bur (_Solanum rostratum_), Blue Vervain (_Verbena hastata_), +Mullein (_Verbascum Thapsus_), Ragweed, Asters, and a few Prickly Pear +(_Opuntia humifusa_). Two small areas on the pasture completely lacked +vegetation; these may have been wallows or the sites of old +salt-licks. + +Three shallow stock ponds, behind earthen dikes in ravines, were +present on the pasture. The pond near the farm buildings ("House +Pond") and that in the southwestern part of the pasture ("Far Pond") +were present when studies of box turtles were begun. The largest pond, +in a deep ravine in the northern part of the pasture, was constructed +in June, 1956, and became filled in approximately one month (Pls. 16 +and 18). Pond embankments were chiefly bare of vegetation because of +trampling by cattle; in a few places at the edge of the water, or in +places too steep for cattle to walk, there were small patches of +weeds, sedges, and Slough Grass. The ponds contained some water at all +times of the year. The only vertebrates permanently inhabiting the +ponds in the course of my studies were Bullfrogs (_Rana catesbeiana_) +and Leopard frogs (_Rana pipiens_). + +The three parts of the pasture in which studies were concentrated were +designated as separate subdivisions. The northwest corner area (28 +acres) was triangular and bounded on two sides by rock fences and on +its third side by a deep ravine. The southern ravine area (17 acres) +constituted the part of the lower southern hillside drained by a +series of ravines. The house pond area (seven acres) surrounded "House +Pond." Habitat in these three subdivisions of the pasture was +especially favorable for box turtles. + + +Materials and Methods + +Observations were made at the Damm Farm on 102 days in the two-year +period beginning in Autumn, 1954; observations were concentrated in +the period from May to October although some observations were made in +every month, January and February excepted. Field work was done +chiefly in daylight hours but a few trips were made to the study area +at night. + +Routine handling of each turtle captured at the Damm Farm consisted +of: marking, weighing and measuring turtle; recording the exact place +of capture, body temperature and environmental temperature; and, +recording miscellaneous items such as the presence of ectoparasites, +injuries, distinctive markings, and in some instances, the approximate +age of the turtle. + +Excursions on the Damm Farm were made on foot in 1954 and 1955, and, +in 1956, on horseback. By using a horse, more ground could be covered +per unit of time, a better view could be obtained of immediate +surroundings, and, cattle on the area, being accustomed to horses, did +not become agitated as they would when unmounted persons were nearby. + +The entire study area could not be inspected thoroughly in a single +day. It was usually more profitable to find and mark turtles along +fences, in ravines, or in other open areas, and subsequently to follow +their movements away from these areas by means of trailing threads. +Turtles could be observed from a distance through binoculars. +Cultivated areas were regularly scanned with binoculars but turtles +were seldom seen there. Behavior was observed by sitting motionless on +rock fences or in a blind on top of a stepladder. + +No box turtles were removed from the study area. Specimens obtained in +other areas were used for studies of growth, reproduction, and food +habits. Measurements, weights, and data concerning temperature and +ectoparasites were obtained from specimens collected elsewhere as well +as from individuals on study areas. + +Turtles were obtained by hand-collecting and in unbaited traps; the +number captured in a single day ranged from 12 to none. Traps, like +those used by Packard (1956:9) for tree squirrels, were set in the +mouths of burrows and dens, or--with leads to channel animals into the +trap--along ravines and rock fences. Traps set in the open were +covered to prevent death of turtles from overheating in direct +sunlight. Live-trapping provided much valuable data, although quail, +rabbits, opossums, and box turtles were caught with about equal +frequency in the traps. + +Turtles were marked by notching the marginal scutes of the carapace by +means of a hacksaw blade, following the code system described by Cagle +(1939). Notches, one eighth to one quarter of an inch deep and wide +could be cut more quickly than filed and were more evident than +drilled holes which often became plugged with soil and obscured. +Hatchlings and juveniles were notched with a sharp knife. + +Movements of individual turtles were studied by means of a +turtle-trailing device--similar to the kind first described by Breder +(1927) and later modified by Stickel (1950:355-356)--a tin can, cut to +fit the shell of a turtle, with an axle that bore a spool of thread +(Pl. 27, Fig. 1). The device was taped to the turtle; the free end of +the thread was tied to a stationary object. Thread payed out from the +spool through a guide-loop and marked the course of the turtle as it +moved away from the starting point. Because of its great strength and +elasticity (as compared to cotton), nylon sewing thread was used in +trailers. Ordinarily, turtles were unable to break the thread if it +became snarled or was expended. Cattle frequently tangled the thread +and displaced it but did not often break it. Ordinary spools were cut +down on a lathe so they would hold 600 to 800 yards of thread. +Turtle-trailing provided an accurate record of where and how far a +turtle had traveled, and to a lesser extent, the sort of activity in +which the turtle had been engaged (evidence of feeding, forms, or +trial nest holes). Trailers seemed not to alter the normal activity of +turtles. + +Prominent landmarks were rare or wanting in most places on the +pasture. Locations of captures (or reference points in the movements +of trailer-turtles) were determined by triangulation with a Brunton +compass, using trees along fences as known points of reference. Rough +maps were made in the field and used later, along with compass +readings and measurements, to make a more precise record of movements +and captures on a large map (scale, 100 feet to one inch) of the study +area. Mapped points of capture in grassy areas were accurate within +ten to twenty feet; points of capture in areas where landmarks were +nearby were nearly exact. Areas were measured with a planimeter; +distances traveled by individuals were measured with a cartometer. + +Turtles were measured in the field to the nearest millimeter with +large wooden calipers (of the type used by shoe salesmen) and a clear +plastic ruler. Measurements in the laboratory, especially in studies +of growth, were made, to the nearest tenth of a millimeter with dial +calipers. Measurements made on each specimen examined in the field +were: length of carapace, width of carapace, length of plastron (sum +of lengths of forelobe and hind lobe), width of plastron (at hinge), +and height. All measurements were made in a straight line. A spring +scale of 500 gram capacity, used in the field, gave weights accurately +within three grams. A triple-beam balance was used in the laboratory. +Unless otherwise noted, measurements are expressed in millimeters and +weights are expressed in grams. + +Body temperatures were taken by means of a quick-reading Schultheis +thermometer inserted into the distal portion of the large intestine +with the bulb directed ventrally to avoid puncturing the bladder. Body +temperature of turtles were altered little or not at all in the few +seconds the turtles were held and no attempt was made (except for +small juveniles) to insulate them from the warmth of my hands. Data +recorded with body temperature were: air temperature (in shade, +approximately one inch from turtle); ground temperature (or water +temperature); behavior of turtle; weather conditions; nature of +vegetation or other cover; and, time of day. Unless otherwise noted, +temperatures are expressed in degrees Centigrade. + +A maximum-minimum thermometer was installed near the buildings at the +Damm Farm. Notes on general weather conditions were made on each visit +to the study area. Additional climatological data were obtained from +the U. S. Weather Stations in Topeka and Lawrence, from records at the +Reservation, and from official bulletins of the U. S. Weather Bureau. + +Stomachs and gonads were removed and preserved by standard techniques +soon after specimens were killed. The dates given to gonads were, in +all instances, the dates when the specimens were killed. Eggs were +prepared for incubation in the manner described by Legler (1956). +Females laying or containing eggs used in studies of incubation were +preserved for further studies and comparison with young hatched from +the eggs. Histological preparations were fixed in ten per cent +formalin or Bouin's fluid, embedded in paraffin, and stained with +hematoxalin and eosin. + + +Terminology + +Names used for the epidermal and bony parts of the shell follow the +classification proposed by Carr (1952:35-39). The terms "scute," +"lamina," and "scale" are used here more or less interchangeably for +the epidermal parts as are the terms "plate," "bone," and "element" +for the bony parts of the shell. + +The term "form" is used here in the same sense that Stickel (1950:358) +used it in her study of _T. carolina_--to indicate a depression or +cavity made by a turtle in vegetation or soil. Forms correspond +closely in shape and size to shape and size of the turtle. Forms of +_T. ornata_ differ from those of _T. carolina_ chiefly in being made +most often in soil, over which there is a minimum of vegetational +cover. The term "den" refers to natural cavities (or cavities of +unknown origin) beneath rocks, in rock fences, or in cut banks. The +term "burrow," unless otherwise noted, refers to burrows made by +animals other than box turtles. + + + + +HABITAT AND LIMITING FACTORS + + +The known range of _T. ornata_ includes the southern half of the +Grassland Biome, part of the Desert Biome, and that part of the +Temperate Deciduous Forest Biome known as the Prairie-Forest Ecotone. +The species is found in microhabitats that differ widely in food +supply, temperature, moisture, and kind of soil. In spite of its +relatively high degree of morphological specialization, _T. ornata_ is +remarkably versatile in regard to habitat requirements. + +Ornate box turtles are relatively inconspicuous in natural +surroundings and collectors seldom seek out and obtain specimens under +completely natural conditions as may be done with certain other +reptiles and amphibians by turning rocks, tearing apart logs, or +setting traps. Most series of specimens are obtained by hunting after +rains on roads or other natural breaks in vegetational cover. Detailed +information on habitat preferences is lacking. + +Low temperature seems to be an important factor limiting the +distribution of _T. ornata_ in the northern part of its range. Box +turtles, like nearly all other reptiles occurring at these latitudes, +spend the winter in underground hibernacula. The depth to which the +ground freezes in the coldest part of the winter is therefore a +critical factor. The ground freezes to an average depth of 30 inches +or less over most of the range of the species; only in the extreme +northern part of the range (southern South Dakota, southeastern +Wyoming) does the ground freeze to an average depth of as much as 35 +inches. Average depth of freezing is, in fact, less than 15 inches +over more than one half the range of the species. The average number +of frost-free days per year ranges from 130 to 140 days in the +northern part of the range to more than 250 days in the southwestern +part of the range. + +_Terrapene ornata_ occurs from near sea level to elevations of more +than 5000 feet. Both subspecies are found at both high and low +elevations but _luteola_ is more consistently taken at high elevations +than _ornata_. The latter subspecies commonly occurs at elevations +above 4000 feet on the high plains in extreme western Kansas and +eastern Colorado; the highest elevation from which I have examined +specimens of _T. o. ornata_ is between 4600 and 4700 feet near Akron, +Washington County, Colorado. The greater part of the known range of +_T. o. luteola_ lies above 3000 feet. + +Norris and Zweifel (1950:1) observed _T. o. luteola_ on the Jornada +del Muerto, an elongate plain approximately 4500 feet high, in +southeastern Socorro County, New Mexico; box turtles were abundant on +the level part of the plain and on the bordering foothills but not at +higher elevations where the substratum was rocky. The authors +otherwise noted no preference for any kind of soil. The principal +elements of the plant associations in which the turtles were found +were creosote bush, yucca, mesquite, juniper, tarbush, and grasses. +Lewis (1950:3) reported that _T. ornata luteola_ inhabited the +yucca-grassland zone in Dona Ana County, New Mexico; he stated (_op. +cit._: 10) that individuals were commonly found on roads after rains +and in cloudy weather. No specimens were taken at altitudes higher +than 4300 feet. + +I have examined specimens of _luteola_ from elevations of +approximately 5500 feet in Cochise County, Arizona, and Lincoln +County, New Mexico. These localities are probably at or near the +maximum elevation at which the species occurs. The texture of the +substrate is the most important factor limiting vertical distribution. +Ornate box turtles, like nearly all other turtles, excavate nests; _T. +ornata_ is a burrower, at least for purposes of hibernation. +Populations of the species, therefore, could not survive in areas of +hard unyielding substrata. Such substrata seem to be the most +important factor limiting altitudinal distribution. + +Most of the area in which _T. ornata_ occurs is semiarid or arid. +Average precipitation in the warm season (April through September) +varies from approximately 25 inches in the northeast to less than ten +inches in the southwest. In drier parts of the range, precipitation is +unevenly distributed over the warm season. Long, hot, dry periods are +unfavorable for reptilian activity. _T. ornata_, like many other +reptiles inhabiting dry regions, survives long periods without water +by seeking shelter (usually underground) and remaining quiescent. +Populations of the subspecies _luteola_ live under far more rigorous +conditions in this respect than do the more northern populations. +Specimens of _luteola_ from Arizona that were kept for several years +in the laboratory under dry conditions and fed adequately, but at +infrequent intervals, were able to remain healthy and even to grow +whereas examples of _ornata_ kept under the same conditions soon +languished and died; _luteola_ seems to be physiologically adapted for +existence under arid conditions, where normal activity is sometimes +possible for only a few weeks in the year. + +The prairies of Nebraska, Kansas, Oklahoma, and northern Texas seem to +provide the most nearly optimum habitat for the species; in these +regions box turtles are active on a large majority of the days from +April to October in years having average or better than average +precipitation and population density seems to be greater than in the +more arid parts of the range. + +Activities of man have probably affected the density of populations of +the ornate box turtle in many parts of its range but appear not to +have acted as limiting factors except in certain areas along the +northern edge of the range (Blanchard, 1923:19-20, 24) where +disruption of grassland through intensive cultivation probably has +excluded the species. Unlike certain other reptiles of the Great +Plains (Fitch, 1955:64), _T. ornata_ seems not to have been +affected--either by direct decimation of populations or by disruption +of habitat--by intensive zoological collecting in restricted areas. +Environmental changes such as those resulting from overgrazing and +erosion, or from protection of the habitat from grazing could be +expected to cause long-term changes in populations of ornate box +turtles. + +_Terrapene o. ornata_ is an omnivorous, opportunistic feeder, +primarily insectivorous but able to subsist on nearly any sort of +animal or vegetable food. The general food habits of _luteola_ are +poorly known but probably resemble those of _ornata_. Although kind of +food available probably does not limit the distribution of _T. ornata_ +there are indications that it influences population density. In +Kansas, for example, dung insects are an important staple in the diet +and box turtles were found always to be more numerous in areas where +domestic cattle provided an abundant supply of dung than elsewhere. A +similar relationship probably existed in former times between box +turtles and native ungulates. Near extinction of buffalo in the Great +Plains possibly caused a decrease in populations of box turtles. Henry +S. Fitch told me that the number of _T. ornata_ at the Reservation +gradually declined after cattle were removed from the area in 1948. + +In summary, the distribution of _T. ornata_ seems to be limited by: 1) +Presence of a substrate too hard to permit digging of nests and forms +(southwestern and western edges of range); 2) temperatures causing the +ground to freeze deep enough (approximately 30 inches) to kill turtles +in hibernacula (northern edge of range); and, 3) the lack of one or +more relatively wet periods in the course of the warm season, +preventing at least temporary emergence from quiescence (southwestern +edge of range). + + + + +HABITAT IN KANSAS + + +Clarke (1958:40-45) reported _T. o. ornata_ in all terrestrial +communities studied in Osage County; he considered the subspecies to +be characteristic of the "... cultivated-field community ..." and to +be of frequent occurrence in (but not characteristic of) the "... +Oak-Walnut Hillside Forest ..., Buckbrush-Sumac ..., and Prairie +communities ...". Brennan (1937:345) found _T. o. ornata_ to be +equally abundant in mixed prairie and prairie-streamside habitats in +Ellis County; the subspecies was much rarer on rocky hillsides and in +the habitat surrounding prairie ponds. Carpenter (1940:641) listed _T. +o. ornata_ as an inhabitant of "... tall and mixed-grass prairies ..." +(also in Oklahoma and Nebraska). Fitch (1958:99) found the order of +preference for habitats at the Natural History Reservation to be +grazed pasture land, woodland, open fields with undisturbed prairie +vegetation, and fallow fields with a rank growth of weeds. + +At the Damm Farm the greatest number of box turtles was collected on +the pasture, especially in three areas designated in Plate 1 as the +"northwest corner," "southern ravine," and "house pond" areas. These +three areas had several features in common. All contained ravines and +rocky slopes that provided many places of concealment (dens, burrows +of larger animals, and suitable substrate for the excavation of +earthen forms). All contained water (in ponds and intermittent +streams) for most of the year; and, all were frequented daily by +cattle that left an abundant supply of dung in which box turtles +foraged. In addition, each of the three areas contained at least one +mulberry tree, under which fruit was abundant in the months of June +and July. + +The relative numbers of box turtles found in different areas on the +Damm Farm were, of course, governed to some extent by my activity in +these areas and by the relative ease with which box turtles were seen +in different types of vegetational cover. Turtles were more easily +seen in the pasture (especially in sparsely vegetated or denuded +areas) where much of my field work was done on horseback, than in the +wooded areas, where excursions were usually made on foot. It was +evident, however, after mapping known ranges and studying patterns of +movement in marked turtles, that concentrations in the three +above-mentioned areas of pasture were an indication of actual +preference by turtles for the more favorable habitat in these areas +rather than the result of incomplete sampling. + + + + +REPRODUCTION + + +Mating + +Mating takes place throughout the season of activity but is most +common in spring--soon after emergence from hibernation--and in +autumn. Turtles frequently copulated in the laboratory in spring and +autumn. Copulation was observed under natural conditions on several +occasions but only once at the Damm Farm. + +Norris and Zwiefel (1950:4) saw two captive individuals of _T. o. +luteola_ copulating on 12 August; copulation lasted two hours. +Brumwell (1940:391-2) gave the following description of mating in _T. +o. ornata_. A male pursued a female for nearly half an hour, first +nudging the margins of her shell and later approaching her rapidly +from the rear and hurling himself on her back in an attempt to mount, +at the same time emitting a stream of liquid from each nostril. The +liquid was presumably water; both sexes had imbibed water in a pond +just before courtship began. Brumwell suggested that pressure on the +plastron of the male had forced the water out his nostrils. The pair +remained in the coital position for 30 minutes after the male had +achieved intromission. In another instance, Brumwell (_loc. cit._) saw +four males pursuing a single female, the males exhibiting the same +behavior (nudging and lunging) outlined above. Males that attempted to +mount other males were repelled by defensive snapping of the +approached male. The female also snapped at some of the males that +tried to mount her. One male was finally successful in mounting and +was henceforth unmolested by the other males. Brumwell suggested that +shell biting and tapping may be methods of sex-recognition. + +In the several instances of mating that I observed, the male, after +mounting the shell of the female (Pl. 28), gripped her, with the first +claws of his hind feet, just beneath her legs or on the skin of the +gluteal region and, with the remaining three claws, gripped the +posterior edges of her plastron. In most instances the female secured +the male's legs by hooking her own legs around them. The coital +position of _T. ornata_ seems to differ from that of _T. carolina_, at +least in regard to the position of the male's legs. The coital +positions of _T. carolina_ illustrated by Cahn (1937:94, Fig. 13) are +physically impossible for _T. ornata_. + +In _T. ornata_ the pressure exerted on the male's legs by the female +probably impairs circulation and probably is painful to the male, +especially after coitus, when the male falls backward but is still +held by the female. The heavily developed musculature of the legs of +males may be an adaptation to strengthen the legs for this temporary +period of stress. Evans (1953:191) and Cahn and Conder (1932:87-88) +observed the hind legs of males of _T. carolina_ to be noticeably +weakened after copulation, causing the males to remain inactive for +several hours. + +Evans (_op. cit._) observed 72 matings of _T. carolina_ and divided +the process into three phases as follows: 1) circling, pushing and +biting by the male; 2) mounting (female with shell closed); and, 3) +coition (female with shell open). Penn and Pottharst (1940:26) +reported that captive _T. carolina_ in New Orleans mated chiefly under +conditions of optimum temperature (21 to 27A deg. C.) and high humidity; +some matings took place in a pool of water. Males pushed females about +after mating, often rolling them over several times. + +Because ornate box turtles observed by me were able easily to right +themselves from an inverted position on substrata of all kinds, males +left lying on their backs after copulation are probably in no danger +of perishing in this position, as was suggested by Allard (1939) for +_T. carolina_. + + +Insemination + +Oviducts of several females were flushed by means of a pipette to +determine whether they contained sperm. Approximately half of the +females captured in May, 1956, had sperm in their oviducts, but +females captured in June and July did not. Sperm flushed from the +oviducts were in clumps of several hundred and showed no sign of +motility a few minutes after the female was anesthetized with +chloroform. No sperm were found in the oviducts of immature females +but one female of nearly adult size was observed in copulation with a +mature male. + +Thorough examination of microscopic sections of oviduct (taken at +various times in the season of activity) usually revealed a few sperm +lodged in the folds (Pl. 19, Fig. 8) of the cephalic as well as the +caudal portion of the tube, but no specialized seminal receptacles +such as occur in snakes (Fox, 1956) were present. Fertilization +without reinsemination probably occurs in _T. ornata_. Ewing (1943) +and Finneran (1948:126) reported that females of _T. carolina_ +produced fertile eggs for periods of four and two years, respectively, +after being removed from all contact with males. + + +Sexual Cycle of Males + +Testes were preserved in each month from April to October. The +following description of spermatogenesis is based chiefly on material +collected in 1955, although testes were preserved also in 1954. +Comparison of material obtained in 1954 and 1955 revealed that +spermatogenesis began earlier and was more advanced on any given date +in 1955 than in 1954. + +Testes of mature individuals are pale yellow and slightly oblong. The +epididymis is ordinarily dark brown or black and contrasts sharply +with the color of the testes. Size of testes was expressed as the +average length (greatest diameter) of both testes. Testes are smallest +in April, immediately after emergence from hibernation, and largest in +early September (Pl. 20, Figs. 3-4). They are nearly spherical when of +maximum size; increase in bulk, therefore, is relatively greater than +the increase in size shown in Figure 3. They increase in size from +April until early June, recede during most of June, and again increase +in size in July and August. They remain large from early September +until hibernation is begun, becoming only slightly smaller in late +September and October. + +Increase in size following emergence from hibernation may be due in +part to proliferation of the sustentacular cytoplasm. Decrease in size +in early June is correlated with the end of the period of most active +mating; maximal size is coincident with the peak of the spermatogenic +cycle in early September. + + [Illustration: FIG. 3. Seasonal fluctuations in size (average + greatest diameter) of testes in _T. o. ornata_ as determined + by examination of 40 specimens from eastern Kansas.] + +Spermatogenesis (refer to Pl. 19, Figs. 1-5) begins in early May when +a few spermatogonia appear in the seminiferous tubules. The +histological appearance of testes preserved in April and May is much +the same. Nuclei of Sertoli cells, which outnumber the spermatogonia, +are evident at the periphery of the tubules and the clear cytoplasm of +the cells extends into and nearly fills the lumina. The few darkly +stained spermatids that are present in April are cells that probably +were produced in the previous summer. Sperm are present in small +groups within the sustentacular cytoplasm, but ordinarily are absent +in the lumina. + +Primary spermatocytes appear in the tubules from mid-May to early +June. By mid-May there are practically no sperm at any place in the +tubules. The sustentacular cytoplasm has a less compact arrangement in +late May than in April. + +Spermatogenesis is well under way by mid-June; at this time, two or +three distinct layers of primary and secondary spermatocytes are +present and these cells outnumber the Sertoli cells. The lumina are +filled with cellular detritus and are no longer bordered by a clear +ring of sustentacular cytoplasm. No sperm are present. + +Spermatids appear in late June and a few of them undergo metamorphosis +in early July; by mid-July, spermatids and secondary spermatocytes are +the dominant cells in the seminiferous tubules, although +spermatogonia are still active. + +By late August, clusters of sperm and metamorphosing spermatids +surround the Sertoli cells; large numbers of sperm as well as sloughed +cells representing various spermatogenic stages are present in the +lumina. Secondary spermatocytes are still evident near the periphery +of the tubules but they are much less numerous than spermatids. The +germinal epithelium is still semiactive and small groups of primary +spermatocytes are present in nearly all of the tubules. + +The spermatogenic cycle is completed in the latter half of October +when most of the spermatozoa pass into the epididymides. A few +spermatozoa and spermatids remain in the seminiferous tubules during +hibernation. Although no testicular material was obtained from +hibernating turtles, comparisons of sections made in October and April +show that the germinal epithelium remains inactive from autumn until +spring. Possibly some spermiogenesis takes place in the early phases +of hibernation or in the period in late autumn when turtles are +intermittently active. It is uncertain whether the reorganization of +the sustentacular cytoplasm occurs in autumn, in spring, or in the +course of hibernation. + +The seminiferous tubules of immature males are small, lack lumina, and +contain a few large but inactive spermatogonia (Pl. 19, Fig. 6). The +testes of specimens that were nearly mature contained primary and +secondary spermatocytes but lacked lumina; it was thought that such +individuals would have matured in the following summer and bred in the +following autumn. + +Mature sperm were found in epididymides at all times of the year but +were most numerous in spring and autumn, the period between +spermatogenic cycles (Pl. 19, Fig. 7). Sperm expelled from the +epididymides in autumn matings are seemingly replaced by others from +the seminiferous tubules; the epididymides become much smaller when +their supply of sperm is nearly exhausted after spring mating. + +Risley (1938:304) found the testes of the common musk turtle, +_Sternotherus odoratus_, to be largest in August and smallest in early +May. Recession of testes in spring was coincident with the period of +active breeding; increase in size, later in the season, corresponded +to increasing spermatogenic activity and enlargement of seminiferous +tubules. Altland (1951:600-603) found the spermatogenic cycle of +_Terrapene carolina_ to be nearly like that of _Sternotherus +odoratus_. Fox (1952) found that testes of garter snakes (_Thamnophis +sirtalis_ and _T. elegans_) in California reached a peak of +spermatogenic activity in midsummer, regressed in the latter half of +the summer, and were inactive in winter. + +The spermatogenic cycle of _T. ornata_ as here reported, differs in no +important respect from those of _Thamnophis_, _Sternotherus odoratus_, +or _Terrapene carolina_, except that in _T. ornata_ the cycle begins +and ends somewhat later in the season of activity. In most of the +lizards that have been studied (Fox, 1952:492-3), spermatogenesis +reaches a peak in spring (more or less coincident with the mating +period and with ovulation) and the germinal epithelium remains active +in winter. _Sternotherus_, _Terrapene_, and _Thamnophis_ are alike in +completing spermatogenesis late in the season and storing spermatozoa, +in the seminiferous tubules or in the epididymides, during +hibernation. + +It is noteworthy that, in the turtles and snakes mentioned above, +sperm produced in autumn are used to fertilize eggs laid in the +following year, and mating [with the exception of _Thamnophis +elegans_, (Fox, 1956)] occurs in both spring and autumn. It is not +definitely known in any of these instances, whether sperm resulting +from autumn or spring inseminations (or both) fertilize the eggs. +Risley (1933:693) found motile sperm in the oviducts of female +_Sternotherus odoratus_ that had recently emerged from hibernation; +he believed that spring mating, although it commonly occurred, was not +necessary to fertilize eggs. Disadvantages, if any, of completing +spermatogenesis well in advance of ovulation seem to be at least +partly counteracted by two annual mating periods or by mating +throughout the season of activity. + +Sexual Cycle of Females + +The following account of oA¶genesis is based on examination of +preserved ovaries from 68 mature specimens. The ages of most specimens +were known, inasmuch as the specimens were used in studies of growth +as well as gametogenesis. Other data were obtained from adult females +that were dissected but not preserved, and from immature females. + + [Illustration: FIG. 4. Seasonal fluctuations in ovarian weight + in _T. o. ornata_, as determined by examination of 60 specimens + from eastern Kansas.] + +Size of ovarian follicles was determined by means of a clear plastic +gauge containing notches 5, 10, 15, 20, and 25 millimeters wide. The +number of follicles within a given size range could be quickly +determined by finding the smallest notch into which the follicles fit. +It was necessary to weigh all ovaries after preservation since some of +them had not been weighed when fresh. Since all ovarian samples were +preserved in the same manner, weights remained relatively the same. +Preserved material was lighter than fresh by an average of 13 per +cent. Follicles less than one millimeter in diameter were not counted. +Corpora lutea and corpora albicantia were studied under a binocular +dissecting microscope. No histological studies were made of the female +reproductive system. + +Ovarian follicles and oviducal eggs were recorded separately for the +right and left sides. Each ovary was always kept associated with the +oviduct of the same side, but in some instances it was not recorded +whether the organs were left or right. + +Ovaries ordinarily weighed most in October, March, and April, when +most females contained enlarged follicles, and least in August and +September when the supply of enlarged follicles was usually exhausted +(Figs. 4 and 5). + + [Illustration: FIG. 5. The seasonal occurrence of enlarged + ovarian follicles in females of _T. o. ornata_, expressed, + For each month, as the percentage of total females that + contained two or more follicles having diameters greater than + 15 mm. Total number of females in each of the samples is shown + in parentheses at the top of each bar.] + +The ovarian cycle begins in July or August, after ovulation has +occurred. At that time many minute follicles form on the germinal +ridges of the ovaries. On the basis of the material that I examined, +it seems that ovarian follicles either grow to nearly mature size in +the season preceding ovulation and remain quiescent over winter or +grow rapidly in the period of approximately six weeks between spring +emergence and ovulation. Altland (1951:603-5) reported that the former +condition was the usual one in _T. carolina_; he suggested that +possibly some of the enlarged follicles were absorbed during +hibernation. + +Examination of yolks of oviducal eggs revealed that follicles mature +when they reach a diameter of 16 to 20 millimeters and a weight of two +to two and one-half grams (Pl. 20, Fig. 1). + +The enlarged follicles remaining on the ovaries after ovulation +(excluding those smaller than six mm.) can be grouped according to +diameter as: large (greater than 15 mm.), medium (11 to 15 mm.), and +small (six to 10 mm.). Ten females collected in the period from June 2 +to 8, after they had ovulated, all had follicles falling in at least +one of these size groups, and eight had follicles falling in two or +more of the groups. In females having enlarged follicles of more than +one of the size groups, there were several follicles in each of two +groups and no follicles, or only one follicle, in the remaining group. +Enlarged follicles represent future clutches but whether the enlarged +follicles will be ovulated in the same season or in a later season is +questionable. + +Evidence found in the present study suggested that at least a few +females lay more than one clutch of eggs per year. Among 34 specimens +obtained in June and July, eight (24 per cent) had corpora lutea (or +easily discernible corpora albicantia) and at least two follicles more +than 15 millimeters in diameter; in three specimens (9 per cent) the +ovaries bore fresh corpora lutea (representing recent ovulations) and +a set of older corpora lutea (representing ovulations that had +occurred several weeks previously). It was thought that each of these +eleven females (33 per cent of sample) had produced or would have +produced two clutches of eggs in the season of its capture. The number +of large follicles present after the first set of ovulations (mean, +3.5) was fewer in most instances than the average clutch-size (see +below), indicating that second clutches are smaller than first +clutches. Smaller second clutches were found also in _T. carolina_ +(Legler, 1958). + +Further evidence for multiple clutches was the absence of enlarged +ovarian follicles in some females obtained in September. Atretic +follicles, ordinarily orange, brown, or purplish, were observed on the +ovaries of many of the females examined; in most instances, not more +than two follicles of the small or medium size groups were atretic. +Atresia was in no instance great enough to account for the complete +loss of enlarged follicles. + +Further study probably will show that many of the females laying in +May and early June lay again before the end of July, and that eggs in +the oviducts of females captured in the latter month frequently +represent second clutches. Under favorable conditions, eggs laid by +the end of July would have a good chance of hatching before the advent +of cold weather in autumn; turtles hatching too late to escape from +the nest could burrow into its sides and probably escape freezing +temperatures. + +Cagle's findings concerning _Pseudemys scripta_ (1950:38) and +_Chrysemys picta_ (1954:228-9) suggest that these species lay more +than one clutch per season, at least in the southern parts of their +ranges. Carr (1952) indicated that multiple layings were known in most +species of marine turtles (families Dermochelydae and Chelonidae) and +strongly suspected in other species. Other turtles recorded to have +produced multiple clutches in a single season (based chiefly on +captive specimens or cultured populations) include: the starred +tortoise, _Geochelone elegans_ (Deraniyagala, 1939:287); the Asiatic +trionychid, _Lissemys punctata_ (_op. cit._:304); the diamond-backed +terrapin, _Malaclemys terrapin_ (Hildebrand and Prytherch, 1947:2); +and the Japanese soft-shelled turtle, _Trionyx japonicus_ (Mitsukuri, +1895, cited by Cagle, 1950:38). + +There is a marked alternation of ovarian activity in _T. ornata_, one +ovary being more active than its partner in a given season. The less +active ovary is more active than its partner in the following season. +For example, a specimen killed in July had four corpora lutea on the +right ovary and two on the left and there were five enlarged follicles +(of the medium size group), representing the next set of eggs to be +ovulated, four on the left ovary and one on the right. Similar +alternation of ovarian activity was observed, to a greater or lesser +extent, in nearly all of the females examined. Many subadult females +that were approaching their first breeding season (as evidenced by the +presence of large ovarian follicles but no indication of former +ovulation) had but one active ovary. This may account in part for the +tendency of small, young females to lay clutches smaller than average. +One ovary may become senile in old females before its partner does; +this may explain the occasional absence or atrophy of one ovary in +large females that I have examined. + +In all the specimens examined, it was evident that ovulation had +occurred or would occur in two successive seasons. Senile or young +females might, however, be expected to skip a laying season if only +one ovary was functioning. + +After ovulation, the collapsed follicle assumes a cuplike shape and +becomes a glandular corpus luteum (Pl. 20, Fig. 2). Corpora lutea are +approximately eight millimeters in diameter and are easily discernible +at least until the eggs are laid; they are somewhat less distinct +after preservation. Corpora lutea undergo rapid involution following +oviposition and, after two to three weeks, are little more than small +puckerings on the ovarian epithelium. At this stage they are properly +referred to as corpora albicantia and are discernible only after +careful examination of the ovary under low magnification. Corpora +albicantia remain on the ovary until April of the year following +ovulation but disappear in May and are never present after the new set +of eggs is ovulated. Ovaries of some subadults (that would have laid +first in the season following capture) contained enlarged follicles +and, but for their lack of corpora lutea and corpora albicantia, were +indistinguishable from those of older, fully mature females. + +Altland (1951:605-610) gave a histological description of the corpus +luteum of _Terrapene carolina_. Corpora lutea were glandular and +filled with lipoidal material until the eggs were laid. Atresia of +corpora lutea began when eggs were laid, was completed by mid-August, +and was coincident with atresia of large follicles that did not +undergo ovulation. Altland did not describe the gross external +appearance of the corpus albicans. + +The corpus luteum of oviparous reptiles seems to be closely associated +with the intrauterine life of the eggs and, in viviparous reptiles, it +may be an important factor in maintaining optimum gestational +environment; however, its functions in all reptiles are poorly +understood (Miller, 1948:200-201). + +Information gleaned from records of gravid females and known dates of +nesting suggests that eggs are retained in the oviducts two to three +weeks before laying. Once they are ovulated, the eggs are exposed to +but few hazards until laid; counts of corpora lutea are an accurate +indication of the number of eggs laid. In the gravid females examined +by me, number of corpora lutea on the ovaries was equal, in all but +one instance, to the number of oviducal eggs. In the single instance +in which an extra corpus luteum was found, one egg had probably been +laid before the specimen was captured. The high incidence of +correspondence between counts of corpora lutea and counts of oviducal +eggs indicates also that _T. ornata_ deposits the entire complement of +oviducal eggs at one time, not singly or in smaller groups. + +Extrauterine migration of ova, whereby eggs from one ovary pass into +the oviduct of the opposite side, is of common occurrence in _T. +ornata_ and is known to occur also in _T. carolina_, _Chrysemys +picta_, _Emydoidea blandingi_, _Pseudemys scripta_, _Cnemidophorus +sexlineatus_, and in several mammals (Legler, 1958). This ovular +migration may serve to redistribute eggs to the oviducts when the +ovaries are functioning at unequal rates. + +The eggs acquire shells soon after they enter the oviducts. No +shell-less eggs were found in oviducts but several specimens of _T. +ornata_ had oviducal eggs, the thin, parchmentlike shells of which +lacked the outer calceous layer; in these specimens the corpora lutea +were fresh, probably not more than two days old. Eggs that had +remained in the oviducts longer had a calceous layer on the outside of +the shell. Eggs having incompletely developed shells were successfully +incubated in the laboratory. Cagle (1950:38) found shelled but +yolkless eggs in the oviducts of several _Pseudemys scripta_ but found +no yolkless eggs in nests. No yolkless eggs were found in specimens of +_T. ornata_ in the course of the present study. + +The uterine portion of the oviducts becomes darkened (pale gray to +intense black) in the breeding season. Darkening of oviducts seemed to +coincide with the period when eggs were in the oviducts and it +persisted for a variable length of time after the eggs were laid. +Oviducts of immature females were ordinarily pale. + + +Nesting + +Ornate box turtles nest chiefly in June. Some females nest as early as +the first week of May or as late as mid-July but the nesting season +reaches its peak in mid-June. Eggs nearly ready to be laid were in +oviducts (determined by bimanual palpation in the field or by +dissection in the laboratory) of many females captured in June; nearly +half of the records so obtained were in the second week of that month. +Early records of shelled oviducal eggs were April 25 (specimen from +Ottawa County, Oklahoma), May 5, and May 22. The two latest records +are for females retaining oviducal eggs on July 2 and 11. Known dates +for nesting of free-living females were distributed rather evenly +through the month of June. It is worthy of note that all (four) of +the nestings known to occur in July were by captive females. Females +of _T. ornata_, like those of some other turtles (Cagle and Tihen, +1948; Risley, 1933:694), seem to retain their eggs until conditions +are suitable for nesting. Most of the reports in the literature of +nesting after mid-July represent records for captive females. + +Nests of _T. o. ornata_ were so well-concealed that they were +difficult to find even when a gravid female had been followed to the +approximate location by means of a trailing thread. Females spend one +to several days seeking a site for the nest, usually traveling a +circuitous route within a restricted area. Movements of nest-seeking +females were more extensive than those of males and non-gravid females +observed in the same periods. + +Activities of one gravid female, typical in most respects of the +activities of several other gravid females observed (for periods of +one to 23 days) at the Damm Farm, illustrate pre-nesting behavior +(Fig. 29). A trailer was attached to the female on the morning of June +7. She was recovered early on the following afternoon; her movements +in the elapsed period had been restricted to a small, deep, ravine 150 +feet long and 20 to 30 feet wide. She had traversed each edge of the +ravine at least once and had crossed it six or seven times, keeping +mostly to areas on the upper parts of south--or west--facing slopes +where vegetation was sparse or lacking. In six places she had dug into +the ground, probably to test the suitability of the soil for nesting. +In three places she dug beneath rocks that jutted out from the bank, +and in two places merely scratched away the upper crust of soil. Her +most recent attempt at digging (probably late the previous evening or +in early morning on the day of her capture) consisted of a +flask-shaped cavity that, but for the lack of eggs and a covering of +earth, was like a completed nest (Pl. 21, Fig. 1). The cavity was 55 +millimeters deep, 80 millimeters wide at the bottom, and 60 +millimeters wide at the opening. For several inches about the opening +the earth was slightly damp. That piled on the rim of the opening was +of the consistency of thick mud, indicating that the female had voided +fluid first on the surface of the earth and again inside the cavity to +soften the soil. Subsequently during eight days her activities were +similar but not so extensive as on the day described above. It was +determined by daily palpation that she laid her eggs somewhere in the +general area of the ravine on June 15 but the nest could not be found. + + +No completed nests containing eggs were discovered at the Damm Farm +but the locations of several robbed nests and partly completed nests +provided some information on preferred sites. The nests found were on +bare, well-drained, sloping areas and were protected from erosion by +upslope clumps of sod or rocks. The nest cavity illustrated in Plate +21 was at the edge of the sod-line on the upper lip of the west-facing +bank of a ravine. One nest had been excavated in a shallow den beneath +an overhanging limestone rock. Three nests were on west- or +south-facing slopes and one was on the north-facing bank of a ravine. +Box turtles presumably select bare areas for nesting because of the +greater ease of digging. One female at the Damm Farm was thought to +have laid her eggs in a cultivated field and William R. Brecheisen +told me he discovered two nests in a wheat field being plowed in July, +1955. + +The repeated excavation of trial nest cavities presumably exhausts the +supply of liquid in the female's bladder. Frequent imbibing of water +is probably necessary if the search for a nesting site is continued +for more than a day or two. Standing water was usually available in +ponds, ravines, ditches, and other low areas at the Damm Farm in June. +Nesting in June, therefore, is advantageous not only because of the +greater length of time provided for incubation and hatching but also +because of the amount of water available for drinking. Females can +probably be more selective in the choice of a nesting site if their +explorations are not limited by lack of water. + +Females of _T. ornata_, in all instances known to me, began excavation +of their nests in early evening and laid their eggs after dark; Allard +(1935:328) reported the same behavior for _T. carolina_. + +William R. Brecheisen, on July 22, 1955, at his farm, two miles south +and one mile west of Welda, Anderson County, Kansas, observed that a +large female began digging a nest in an earth-filled stock tank at +6:00 P. M. At first she moved her body about on the surface of the +earth, loosening it and pushing it aside with all four legs, making a +depression approximately two inches deep and large enough to +accommodate her body. At 7:30 P. M. she began digging alternately with +her hind feet at the bottom of the depression. Digging continued until +10:00 P. M., at which time the nest cavity was three inches deep, and +three inches in diameter, with a smaller opening at the top. Six eggs +were laid in the next half-hour. Covering of the nest probably took +more than one hour but observations were terminated after the final +egg was laid. By the following morning the nest-site had been +completely covered and was no different in appearance from the rest of +the earthen floor of the tank. (Brecheisen observed more of the +nesting than anyone else has recorded and I am obliged to him for +permission to abstract, as per the above paragraph, the notes that he +wrote on the matter.) + +A nest made by a captive female at the Reservation was of normal +proportions except for an accessory cavity that opened from the neck +of the nest, immediately below the surface of the ground. This smaller +cavity contained a single egg. This peculiar nest may have resulted +from the efforts of two different females since several were kept in +the same outdoor pen. + +Ten adult females were kept in an outdoor cage in the summer of 1955. +The cage was raised off the ground on stilts and its floor was covered +with 12 inches of black, loamy soil. A small pan of water was always +available in the cage and the turtles were fed greens, fruit, and +table scraps each evening. Nesting activity was first noted on June +21, when one of the females was digging a hole in a corner of the +enclosure. She dug with alternate strokes of her fully-extended hind +legs in the manner described (Legler, 1954:141) for painted turtles +(_Chrysemys picta bellii_). Nevertheless, digging was much less +efficient than in _Chrysemys_, because of the narrow hind foot of the +female _T. ornata_; approximately half of the earth removed by any one +stroke rolled back into the nest or was pulled back when she +reinserted her leg. The female stopped digging when I made sudden +movements or held my hand in front of her. Digging continued for +approximately 45 minutes; then the female moved away and burrowed +elsewhere in the cage. The nest cavity that she left was little more +than a shallow depression. Three other females were digging nests +early in the evening on July 3, 5, and 8; in each of these instances +the female stopped digging to eat when food was placed in the cage and +completed the nesting process, unobserved, later in the evening. In +each instance where nest-digging by captive females was observed, the +hind quarters of the female rested in a preliminary, shallow +depression, and the anterior end of the body was tilted upward at an +angle of 20 to 30 degrees. In late June and early July several eggs +were found, unburied, on the floor of the cage and in the pan of +water. + +The excavation of a preliminary cavity by captive females may not +represent a natural phenomenon. Allard (1935) made no mention of it in +his meticulous description of the nesting process in _T. carolina_. It +is worthy of mention, however, that Booth (1958:261) reported the +digging of a preliminary cavity by a captive individual of _Gopherus +agassizi_. + + +Eggs + +The number of eggs in 23 clutches ranged from two to eight (mean, 4.7 +A+- 1.37 [sigma]); clutches of four, five, and six eggs were most +common, occurring in 18 (78 per cent) instances. The tendency for +large females to lay more eggs than small females (Fig. 6) was not so +pronounced as that reported by Cagle (1950:38) for _Pseudemys +scripta_. The small size of _T. ornata_, in comparison with other +emyid turtles, seemingly limits the number of eggs that can be +accommodated internally. The number of eggs per clutch in T. carolina +[2 to 7, average 4.2, Allard (1935:331)], is nearly the same as that +of _T. ornata_. + + [Illustration: FIG. 6. The relation of plastral length to + number of eggs laid by 21 females of _T. o. ornata_ from + eastern Kansas.] + +Shells of the eggs are translucent and pinkish or yellowish when the +eggs are in the oviducts. After several days outside the oviducts the +shells become chalky-white and nearly opaque. Eggs incubated in the +laboratory retained the pinkish color somewhat longer than elsewhere +on their under-surfaces, which were in contact with moist cotton, but +eventually even this part of the shell became white. Infertile eggs +remained translucent and eventually became dark yellow, never becoming +white; they could be distinguished from fertile eggs on the basis of +color alone. Shells of infertile eggs became brittle and slimy after +several weeks. + +The outer layer of the shell of a freshly laid egg is brittle and +cracks when the egg is dented. After a few days, when the eggs begin +to expand, the shell becomes flexible and has a leathery texture. The +shell is finely granulated but appears smooth to the unaided eye. The +granulations are approximately the same as those illustrated by +Agassiz (1857:Pl. 7, Fig. 18) for _T. carolina_. + +Eggs are ellipsoidal. Data concerning size and weight (consisting of +mean, one standard deviation, and extremes, respectively) taken from +42 eggs (representing 9 clutches) within 24 hours after they were +laid, or dissected from oviducts, are as follows: length, 36.06 A+- 2.77 +(31.3-40.9); width, 21.72 A+- 1.04 (20.0-26.3); and weight, 10.09 A+- 1.31 +(8.0-14.3). There was a general tendency for smaller clutches to have +larger eggs; the largest and heaviest were in the smallest clutch (two +eggs) and the smallest were in the largest clutch (eight eggs). Risley +(1933:697) reported such a correlation in _Sternotherus odoratus_, as +did Allard (1935:331) in _T. carolina_. Measurements in the literature +of the size of eggs of _T. ornata_ suggest a width greater than that +stated above, probably because some eggs already had begun to expand +when measured. + +Eggs of _T. ornata_ expand in the course of incubation, as do other +reptilian eggs with flexible shells, owing to absorption of water. In +the laboratory, 48 eggs increased by an average of approximately three +grams in weight and three millimeters in width over the entire period +of incubation; increase in width coincided with decrease in length. +Cotton in incubation dishes was kept moist enough so that some water +could be squeezed from it. When the cotton was constantly moist, eggs +showed a fairly steady expansion from the first week of incubation +until hatching. The process could be reversed by allowing the cotton +to dry. Eggs that were allowed to dry for a day or more became grossly +dented or collapsed. Eggs at the periphery of the incubation dish were +ordinarily more seriously affected by drying than were those at the +center or in the bottom of the dish. A generous re-wetting of +desiccated eggs and cotton caused the eggs to swell to their original +proportions within 24 hours. Recessions occurred, however, even in the +clutches that received the most nearly even amount of moisture. +Increases in weight and size seemed to reach a peak in the middle of +the incubation period and again immediately before hatching. Infertile +eggs expanded in the same manner as fertile eggs in the first week or +two of incubation, but thereafter gradually regressed in bulk or +failed to re-expand after temporary periods of dryness. Fertile eggs +that were in good condition had a characteristically turgid, springy +feel and could be bounced off a hard surface. + +Temporary lack of moisture usually did not kill embryos; prolonged +dryness, combined with high temperatures, probably could not be +tolerated. Lynn and Ullrich (1950), by desiccating the eggs of +_Chrysemys picta_ and _Chelydra serpentina_, produced abnormalities in +the young ranging from slight irregularities of the shell to eyeless +monstrosities; eggs desiccated in the latter half of incubation +produced a higher percentage of abnormal young than eggs that were +desiccated earlier. + +In 1956, three fertile eggs, from clutches that were at different +stages of incubation, were immersed in water for 48 hours. The eggs +rested on the bottom of the bowl in the same position in which they +had been placed in the incubation dishes; when turned, they returned +invariably to the original position. The embryos in two of the eggs +(one and 27 days old at the time of immersion) were still living ten +days after the eggs were removed from the water; the embryo in the +remaining egg (21 days old at the time of immersion) was dead. Eggs +immersed in water increased in size and weight at the same rate as +eggs in incubation dishes, indicating that absorption of water +probably operates on a threshold principle, the amount absorbed being +no more than normal even under wet conditions. + +Natural nests usually are in well-drained areas, but water probably +stands in some nests for short periods after heavy rains. Provided the +nest cavity itself is not damaged, water in the nest is probably more +beneficial than harmful to the eggs; however, nests that are inundated +during floods probably have little chance of survival. + + +Embryonic Development + +Eggs were examined by transmitted light in the course of incubation. +At the time of laying (or removal from oviducts) no embryonic +structures were discernible even in eggs that had been retained in the +oviducts of captive females some weeks past the normal time of laying; +a colorless blastodisc could be seen if eggs were opened. Embryonic +structures first became visible at eight to ten days of incubation; at +this time vascularization of the blastodisc was evident and the eyes +appeared as dark spots. Heart beats were observed in most embryos by +the fifteenth day but were evident in a few as early as the tenth day. +The pulse of a fifteen-day-old embryo averaged 72 beats per minute at +a temperature of 30 degrees. Embryos at fifteen days, measured in a +straight line from cephalic flexure to posteriormost portion of body, +were approximately nine to ten millimeters long and at 22 days were 14 +millimeters long. At approximately 35 days the eggs became dark red; +embryonic structures were discernible thereafter only in eggs that had +embryos situated at one end, close to the shell. + +Incubation periods for 49 eggs (representing 12 clutches) kept in the +laboratory ranged from 56 to 127 days, depending on the temperature of +the air during the incubation period. In 1955, eggs were kept at my +home in Lawrence where air temperatures were uncomfortably hot in +summer and fluctuations of 20 degrees (Fahrenheit) or more in a +24-hour period were common. The following summer eggs were kept in my +office at the Museum where temperatures were but slightly cooler than +in my home and subject also to wide variation. In 1957 this part of +the Museum was air-conditioned and kept at approximately 75 degrees. +The greater lengths of incubation periods at lower temperatures are +shown in Table 1. Risley (1933:698) found the incubation period of +_Sternotherus odoratus_ to be longer at lower temperatures; +corresponding observations were made by Allard (1935:332) and Driver +(1946:173) on the eggs of _Terrapene carolina_. Cagle (1950:40) and +Cunningham (1939) found no distinct differences in length of +incubation period for eggs of _Pseudemys scripta_ and _Malaclemys +terrapin_, respectively, at different temperatures within the range +tolerated by the eggs. + +Most nests observed in the field were in open situations where they +would receive the direct rays of the sun for at least part of the day; +the shorter average incubation periods (59 and 70 days, respectively), +observed in 1955 and 1956, therefore, more nearly reflect the time of +incubation under natural conditions than does the excessively long +period (125 days at 75 degrees) observed in 1957 under cooler, more +nearly even temperatures. + + + TABLE 1.--The Relationship of Temperature and Duration of Incubation + Period as Determined from Laboratory Studies of 49 Eggs of + _T. ornata_. + =============+===================+=========+========+================= + Average | Period of | Number | Number | + daily | incubation (Days) | of | of | Remarks + temperature |--------+----------|clutches | eggs | + (Fahrenheit) | Mean | Range | | | + -------------+--------+----------+---------+--------+----------------- + | | | | | Wide daily + 91 | 59 | 56-64 | 6 | 24 | fluctuations in + | | | | | temperature + -------------+--------+----------+---------+--------+----------------- + | | | | | Wide daily + 82 | 70 | 67-73 | 4 | 21 | fluctuations in + | | | | | temperature + -------------+--------+----------+---------+--------+----------------- + | | | | | Temperature + 75 | 125 | 124-127 | 2 | 4 | thermostatically + | | | | | controlled + -------------+--------+----------+---------+--------+----------------- + + +Sixty-five days seems to be a realistic estimate of a typical +incubation period under natural conditions; eggs laid in mid-June +would hatch by mid-August. Even in years when summer temperatures are +much cooler than normal, eggs probably hatch by the end of October. +Hatchlings or eggs would have a poor chance of surviving a winter in +nests on exposed cut-banks or in other unprotected situations. +Overwintering in the nest, hatchlings might survive more often than +eggs, since hatchlings could burrow into the walls and floor of the +nest cavity. Unsuitable environmental conditions that delay the +nesting season and retard the rate of embryonic development may, in +some years, be important limiting factors on populations of ornate box +turtles. + +In areas where _T. ornata_ and _T. carolina_ are sympatric (for +example, in Illinois, Kansas, and Missouri) the two species occupy +different habitats, _ornata_ preferring open grassland and _carolina_ +wooded situations. Under natural conditions, the average incubation +periods of these two species can be expected to differ, _T. carolina_ +having a somewhat longer period due to lower temperatures in nests +that are shaded. In the light of these speculations, the remark of +Cahn (1937:102)--that _T. ornata_ nested later in the season (in +Illinois) and compensated for this by having a shorter incubation +period--is understandable. + +The range of temperatures tolerated by developing eggs probably varies +with the stage of embryonic development. When temperatures in the +laboratory were 102 to 107 degrees Fahrenheit for approximately eight +hours, due to a defect in a thermostat, the young in two eggs of _T. +ornata_, that had begun to hatch on the previous day, were killed, as +were the nearly full-term embryos in a number of eggs of _T. carolina_ +(southern Mississippi) kept in the same container. A five-day-old +hatchling of _T. ornata_, kept in the same container, survived the +high temperatures with no apparent ill effects. Cagle (1950:41) found +that eggs of _Pseudemys scripta_ could not withstand temperatures of +10 degrees for two weeks nor would they survive if incubated at 40 +degrees. Cunningham (1939) reported that eggs of _Malaclemys terrapin_ +could not survive prolonged exposure to temperatures of 35 to 40.6 +degrees but tolerated temporary exposure to temperatures as high as +46 degrees. + +In the summer of 1955, a clutch of three eggs, all of which contained +nearly full-term embryos, was placed in a refrigerator for 48 hours. +The temperature in the refrigerator was maintained at approximately +4.5 degrees; maximum and minimum temperatures for the 48 hour period +were 2.8 and 9.5 degrees, respectively. When the eggs were removed +from the refrigerator they showed gains in weight and increases in +size comparable to eggs, containing embryos of the same age, used as +controls. The experimental eggs began to hatch two days after they +were removed to normal temperatures--approximately 24 hours later than +the controls. + +In the late stages of incubation, the outer layer of the shell becomes +brittle and is covered with a mosaic of fine cracks or is raised into +small welts. Several days before hatching, movements of the embryo +disturb the surface of the shell and cause the outer layer to crumble +away, especially where the head and forequarters of the embryo lie +against the shell. Some embryos could be seen spasmodically thrusting +the head and neck dorsally against the shell. + +The role of the caruncle in opening the shell seems to vary among +different species of turtles. Cagle (1950:41) reported that it was +used only occasionally by _Pseudemys scripta_; Allard (1935:332) +thought that it was not used by _Terrapene carolina_; and, the +observations of Booth (1958:262) and Grant (1936:228) indicate that +embryos of _Gopherus agassizi_ use the caruncle at least in the +initial rupturing of the shell. + +In the three instances in which hatching was closely observed in _T. +ornata_, the caruncle made the initial opening in the shell; claws of +the forefeet may have torn shells in other hatchings that were not so +closely observed. In all observed instances, the shell was first +opened at a point opposite the anterior end of the embryo. The initial +opening had the appearance of a three-cornered tear. A quantity of +albuminous fluid oozed from eggs as soon as the shells were punctured. + +The initial tear is enlarged by lateral movements of the front feet, +and later the hind feet reach forward and lengthen the tear farther +posteriorly. In many instances a tear develops on each side and the +egg has the appearance of being cleft longitudinally. The young turtle +emerges from the anterior end of the shell or backs out of the shell +through a lateral tear. + +The process of hatching, from rupture of shell to completion of +emergence, extended over three to four days in the laboratory. Many +hatchlings from time to time crawled back into the shell over a period +of several days after hatching was completed. In a clutch of eggs kept +in a pail of earth, by William R. Brecheisen, eight days elapsed +between onset of hatching and appearance of the first hatchling at the +surface. + +A nest in an outdoor pen at the Reservation was discovered in early +October. The cap had been recently perforated and the hatchlings had +escaped. One of them, judged to be approximately two weeks old, was +found in a burrow nearby. The cavity of the nest appeared to have been +enlarged by the young. The eggs were probably laid in early July. +Emergence of young from the nest had been delayed for a time after +hatching, until rain softened the ground in late September and early +October. + + +Fertility and Prenatal Mortality + +Eggs were incubated in the laboratory at more nearly optimum +temperature and humidity than were eggs in natural nests. Percentage +of prenatal mortality probably was lower in laboratory-incubated eggs +than in those under natural conditions. + +Of sixty eggs studied in the laboratory, 45 (75 per cent) were +fertile; 36 (80 per cent) of the fertile eggs (those in which the +blastodisc was at some time discernible by transmitted light) hatched +successfully. In six clutches all the eggs were fertile and five of +these clutches hatched with 100 per cent success. One clutch contained +eggs that were all infertile and another clutch had four infertile +eggs and two fertile eggs that failed to hatch. Among nine fertile +eggs that failed to survive, four casualties occurred in the late +stages of incubation or after hatching had begun, indicating that +these are probably critical periods. + +Fertility of eggs was not correlated with size or age of female, with +size of clutch, or with size of egg. Eggs laid in the laboratory had +higher rates of infertility and prenatal mortality than did eggs +dissected from oviducts. Handling of eggs in removing them from nests +to incubation dishes, after embryonic development had begun, might +have been responsible for reduced viability (Table 2). + + + TABLE 2.--Comparative Rates of Fertility and Prenatal Mortality for + Eggs Dissected from Oviducts and for Eggs That Were Laid in the + Laboratory and Subsequently Removed to Incubation Dishes. + ===========================+==============+=============== + | Eggs removed | Eggs dissected + NUMBER OR PERCENTAGE | from nests | from oviducts + ---------------------------+--------------+--------------- + Number of eggs examined | 22 | 38 + ---------------------------+--------------+--------------- + Percentage of fertile eggs | 64 | 82 + ---------------------------+--------------+--------------- + Percentage of fertile | | + eggs hatched | 50 | 94 + ---------------------------+--------------+--------------- + Percentage of eggs hatched | 32 | 76 + ---------------------------+--------------+--------------- + + +Reproductive Potential + +Assuming that 4.7 eggs are laid per season, that all eggs are fertile +and all hatch, that all young survive to maturity, that half the +hatchlings are females, and that females first lay eggs in the +eleventh year, the progeny of a single mature female would number 699 +after twenty years. Considering that infertility and prenatal +mortality eliminate approximately 40 per cent of eggs laid (according +to laboratory findings) the average number of surviving young per +clutch would be 2.8 and the total progeny, after 20 years, would be +270, provided that only one clutch of eggs was laid per year. But it +is thought that, on the average, one third of the female population +produces two clutches of eggs in a single season. If the second clutch +contains 3.5 eggs (resulting in 2.1 surviving young when factors of +infertility and prenatal mortality are considered), the progeny of a +single female, after 20 years, would number approximately 380. +Postnatal mortality reduces the progeny to a still smaller number. + +The small number of eggs laid each year and the long period required +to reach sexual maturity make the reproductive potential of _T. +ornata_ smaller than that of the other turtles of the Great Plains, +and much smaller than nearly any of the non-chelonian reptiles of the +same region. + + +Number of Reproductive Years + +The total span of reproductive years is difficult to determine; I am +unable to ascertain the age of a turtle that has stopped growing. No +clearly defined external characteristics of senility were discovered +in the populations studied. A male that I examined had one atrophied +testis. In another male both testes were shrunken and discolored and +appeared to be encased by fibrous tissue. Both males were large, well +past the age of regular growth, and had smoothly worn shells. Several +old females had seemingly inactive ovaries. Reproductive processes +probably continue throughout life in most members of the population, +although possibly at a somewhat reduced rate in later life. + + + + +GROWTH AND DEVELOPMENT + + +Initiation of Growth + +Young box turtles became active and alert as soon as they hatched, and +remained so until low temperatures induced quiescence. If sand or soil +was available, hatchlings soon burrowed into it and became inactive. +Covering containers with damp cotton also induced inactivity; the +hatchlings usually made no attempt to burrow through the confining +layer. Desire to feed varied in hatchlings of the same brood and +seemed not to be correlated with retraction of the yolk sac or +retention of the caruncle. Some hatchlings actively pursued mealworms; +on subsequent feedings they learned to associate my presence with food +and eagerly took mealworms from forceps or from my hand. Meat, +vegetables, and most other motionless but edible objects were ignored +by hatchlings but some individuals learned to eat meat after several +forced feedings. Hatchlings that regularly took food in the first +month of life ordinarily grew faster than hatchlings that did not eat. +Many of the hatchlings in the laboratory showed no areas of new +epidermal growth on the shell in the time between hatching and first +(induced) hibernation. + + +Size and Appearance at Hatching + +The proportions of the shell change somewhat in the first few weeks of +life. At hatching the shell may be misshapen as a result of +confinement in the egg. Early changes in proportions of the shell +result from expansion--widening and, to a lesser degree, lengthening +of the carapace--immediately after hatching. Subsequent retraction or +rupture of the yolk sac and closure of the navel are accompanied by a +decrease in height of shell and slight, further widening of the +carapace. + +The yolk sac retracts mainly between the time when the egg shell is +first punctured and the time when the turtle actually emerges from the +shell. When hatching is completed, the yolk sac usually protrudes no +more than two millimeters, but in some individuals it is large and +retracts slowly over a period of several days. + +One individual began hatching on November 11 and was completely out of +the egg shell next day; the yolk sac was 15 millimeters in diameter, +protruded six millimeters from the umbilical opening, and hindered +the hatchling's movements. The sac broke two days later, smearing the +bottom of the turtle's dish with semifluid yolk. The hatchling then +became more active. Twenty-six days later the turtle was still in good +condition and its navel was nearly closed. A turtle that hatched with +a large yolk sac in a natural nest possibly would benefit, through +increased ease of mobility, if the yolk sac ruptured. + +A recently hatched turtle was found at the Reservation in October, +1954, and was kept in a moist terrarium in the laboratory where it +died the following May. The turtle was sluggish and ate only five or +six mealworms while in captivity; no growth was detectable on the +laminae of the shell. Autopsy revealed a vestige of the retracted yolk +sac, approximately one millimeter in diameter, on the small intestine. + +The navel ("umbilical scar") of captive hatchlings ordinarily closed +by the end of the second month but in three instances remained open +more than 99 days. The position of the navel is marked by a +crescent-shaped crease, on the abdominal lamina, that persists until +the plastron is worn down in later years (Pl. 24, Fig. 1). + + [Illustration: FIG. 7. A hatchling of _T. o. ornata_ (A-- 2) that + still retains the caruncle ("egg tooth"). A distinct boss will + remain on the maxillary beak after the caruncle is shed.] + +The caruncle ("egg tooth") (Fig. 7) remains attached to the horny +maxillary beak for a variable length of time; 93 per cent of the live +hatchlings kept in the laboratory retained the caruncle on the tenth +day, 71 per cent on the twentieth day, and only 10 per cent on the +thirtieth day of life. Few individuals retained the caruncle when they +entered hibernation late in November, and none retained it upon +emergence from hibernation. Activities in the first few days or weeks +of life influence the length of time that the caruncle is retained; +turtles that begin feeding soon after hatching probably lose the +caruncle more quickly than do those that remain quiescent. The +caruncles of some laboratory specimens became worn before finally +dropping off. Almost every caruncle present after 50 days could be +flicked off easily with a probe or fingernail. The initiation of +growth of the horny maxillary beak probably causes some loosening of +the caruncle. The caruncle may aid hatchlings in escaping from the +nest. + +After the caruncle falls off, a distinct boss remains, marking its +former place on the horny beak (Pl. 25, Fig. 1); this boss is +gradually obliterated over a period of weeks by wear and by +differential growth, and is seldom visible in turtles that have begun +their first full year of growth. The "first full year of growth" is +here considered to be the period of growth beginning in the spring +after hatching. + +Growth of Epidermal Laminae + +Growth of ornate box turtles was studied by measuring recaptured +turtles in the field, by periodically measuring captive hatchlings and +juveniles, and by measuring growth-rings on the epidermal laminae of +preserved specimens. Studies of growth-rings provided by far the +greatest volume of information on growth, not only for the years in +which field work was done, but for the entire life of each specimen +examined. + +It was necessary to determine the physical nature of growth-rings and +the manner in which they were formed before growth could be analyzed. +Examination of epidermal laminae on the shell of a box turtle reveals +that each has a series of grooves--growth-rings--on its surface. The +deeper grooves are major growth-rings; they occur at varying distances +from one another and run parallel to the growing borders of the +lamina. Major growth-rings vary in number from one to 14 or more, +depending on the age of the turtle (Pl. 22). In juvenal turtles and in +young adults, major growth-rings are distinct and deep. Other grooves +on the shell--minor growth-rings--have the same relationship to the +borders of the laminae but are shallower and less distinct than major +growth-rings. One to several minor growth-rings usually occur on each +smooth area of epidermis between major growth-rings. As the shell of +an adult turtle becomes worn, the minor growth-rings disappear and the +major rings become less distinct. Both sets of rings may be completely +obliterated in old turtles but the major rings usually remain visible +until several years after puberty. + +In cross section, major growth-rings are V- or U-shaped. The inner +wall of each groove is the peripheral edge of the part of the scute +last formed whereas the outer wall represents the inner edge of the +next new area of epidermal growth. The gap produced on the surface of +the lamina (the open part of the groove) results from cessation of +growth at the onset of hibernation. Minor growth-rings are shallow +and barely discernible in cross-section (Fig. 8). It may therefore be +understood that growth-rings are compound in origin; each ring is +formed in part at the beginning of hibernation and in part at the +beginning of the following growing season. + +The few publications discussing growth in turtles express conflicting +views as to the exact mode of growth of epidermal laminae. Carr +(1952:22) briefly discussed growth of turtle scutes in general and +stated that eccentric growth results from an entirely new laminal +layer forming beneath, and projecting past the edges of the existing +lamina. Ewing (1939) found the scutes of _T. carolina_ to be the +thickest at the areola and successively thinner in the following eight +annual zones of growth; parts of scutes formed subsequent to the ninth +year varied irregularly in thickness. He stated that epidermal growth +took place at the margins of the laminae rather than over their entire +under-surfaces. + +It is evident that the mode of scutular growth described by Carr +(_loc. cit._) applies to emyid turtles that shed the epidermal laminae +more or less regularly (for example, _Chrysemys_ and _Pseudemys_). In +these aquatic emyids a layer of the scute, the older portion, +periodically becomes loose and exfoliates usually in one thin, +micalike piece; since the loosened portion of the scute corresponds in +size to the scute below, it must be concluded that a layer of +epidermis is shed from the entire upper surface of the scute, +including the area of new epidermal growth. Box turtles ordinarily do +not shed the older parts of their scutes; the areola and successively +younger portions of the lamina remain attached to the shell until worn +off. The appearance of a single unworn scute, especially one of the +centrals or the posterior laterals, closely resembles a low, lopsided +pyramid. + +Examination of parasagittal sections of scutes revealed that they were +composed of layers, the number of layers varying with the age of the +scute. A scute from a hatchling consists of one layer. A scute that +shows a single season of growth has two layers; a new layer is added +in each subsequent season of growth. Stratification is most evident in +the part of the scute that was formed in the first three or four +seasons and becomes increasingly less distinct in newer parts of the +scute. It may further be understood that scutes grow in the manner +described by Carr (_loc. cit._). + +When the epidermal laminae are removed, a sheet of tough, pale grayish +tissue remains firmly attached to the bones of the shell beneath. This +layer probably includes, or consists of, germinal epithelium. +Contrasting pale and dark areas of the germinal layer correspond to +the pattern of markings on the scute removed. + + [Illustration: FIG. 8. The second central scute from a juvenal + _T. o. ornata_ (KU 16133) in its third full season of growth. + A) Entire scute from above (A-- 2A1/2); dashed line shows portion + removed in parasagittal section. B) Diagonal view of section + removed from scute in "A" (A-- 4-3/8, thickness greatly + exaggerated) showing layers of epidermis formed in successive + seasons of growth. Each layer ends at a major growth-ring + (M 1-3) that was formed during hibernation; minor growth-rings + (m), formed in the course of the growing season, do not result + from the formation of a new layer of epidermis. Note the + granular texture of the areola (a); the smooth zone between the + areola and M1 shows amount of growth in the season of + hatching.] + + +Growth of epidermal laminae is presumably stimulated by growth of the +bony shell. As the bone grows, the germinal layer of the epidermis +grows with it. When growth ceases at the beginning of hibernation, the +thin edges of the scutes are slightly down-turned where they enter the +interlaminal seams (Fig. 8). When growth is resumed in spring, the +germinal layer of the epidermis, rather than continuing to add to the +edge of the existing scute, forms an entirely new layer of epidermis. +The new layer is thin and indistinct under the oldest part of the +scute but becomes more distinct toward its periphery. Immediately +proximal to the edge of the scute, the new layer becomes greatly +thickened, and, where it passes under the edge, it bulges upward, +recurving the free edge of the scute above. At this time the formation +of a major growth-ring is completed. The newly-formed epidermis, +projecting from under the edges of the scute, is paler and softer than +the older parts of the scute; the presence or absence of areas of +newly formed epidermis enables one to determine quickly whether a +turtle is growing in the season in which it is captured. There is +little actual increase in thickness of the scute after the first three +or four years of growth. The epidermal laminae are therefore like low +pyramids only in appearance. This appearance of thickness is enhanced +by the contours of bony shell which correspond to the contours of the +scutes. + +Minor growth-rings differ from major growth-rings in appearance and in +origin. Ewing (_op. cit._: 91) recognized the difference in appearance +and referred to minor growth-rings as "pseudoannual growth zones." +Minor growth-rings result from temporary cessations of growth that +occur in the course of the growing season, not at the onset of +hibernation. They are mere dips or depressions in the surface of the +scute. The occurrence of minor growth-rings indicates that +interruptions in growth of short duration do not result in the +formation of a new layer of epidermis. Slowing of growth or its +temporary cessation may be caused by injuries, periods of quiescence +due to dry, hot, or cold weather, lack of food, and possibly by +physiological stress, especially in females, in the season of +reproduction. Minor growth-rings that lie immediately proximal to +major growth-rings (Pl. 22, Fig. 2), are the result of temporary +dormancy in a period of cold weather at the end of a growing season, +followed by nearly normal activity in a warmer period before +winter-long hibernation is begun. Cagle (1946:699) stated that sliders +(_Pseudemys scripta elegans_) remaining several weeks in a pond that +had become barren of food would stop growing and develop a growth-ring +on the epidermal laminae; he did not indicate, however, whether these +growth-rings differ from those formed during hibernation. + +In species that periodically shed scutes a zone of fracture develops +between the old and new layers of the scute as each new layer of +epidermis is formed, and the old layer is shed. Considering reptiles +as a group, skin shedding is of general occurrence; the process in +_Pseudemys_ and _Chrysemys_ differs in no basic respect from that in +most reptiles. Retention of scutes in terrestrial emyids and in +testudinids is one of many specializations for existence on land. +Retention of scutes protects the shell of terrestrial chelonians +against wear. Some box turtles were observed to have several scutes of +the carapace in the process of exfoliation but no exfoliation was +observed on the plastron. Exfoliation ordinarily occurred on the +scutes of the carapace that were the least worn; the exfoliating +portion included the areola and the three or four oldest (first +formed) layers of the scute. The layer of scute exposed was smooth and +had yellow markings that were only slightly less distinct than those +on the portion that was exfoliating. + +Wear on the shell of a box turtle reduces the thickness of scutes, as +does the shedding of scutes in the aquatic emyids mentioned. It is +noteworthy that any of the layers in the scute of a box turtle can +form the cornified surface of the scute when the layers above it wear +away or are shed. + +It is uncertain whether turtles that have ceased to grow at a +measurable rate continue to elaborate a new layer of epidermis at the +beginning of each season. Greatly worn shells of ornate box turtles, +particularly those of the subspecies _luteola_, have only a thin layer +of epidermis through which the bones of the shell and the sutures +between the bones are visible. I suspect that, in these old +individuals, the germinal layer of the epidermis does not become +active each year but retains the capacity to elaborate new epidermis +if the shell becomes worn thin enough to expose and endanger the bone +beneath it. The germinal layer of old turtles loses the capacity to +produce color. + +Major growth-rings constitute a valuable and accurate history of +growth that can be studied at any time in the life of the turtle if +they have not been obliterated. They are accurate indicators of age +only as long as regular growth continues but may be used to study +early years of growth even in turtles that are no longer growing. +Minor growth-rings, if properly interpreted, provide additional +information on growing conditions in the course of each growing +season. + +Nichols (1939a: 16-17) found that the number of growth-rings formed in +marked individuals of _T. carolina_ did not correspond to the number +of growing seasons elapsed; he concluded that growth-rings were +unreliable as indicators of age and that box turtles frequently +skipped seasons of growth. Woodbury and Hardy (1948:166-167) and +Miller (1955:114) came to approximately the same conclusion concerning +_Gopherus agassizi_. It is significant that these workers were +studying turtles of all sizes and ages, some of which were past the +age of regular, annual growth. Cagle's review of the literature +concerning growth-rings in turtles (1946) suggests that, in most of +the species studied, growth-rings are formed regularly in individuals +that have not attained sexual maturity but are formed irregularly +after puberty. + +Cagle's (_op. cit._) careful studies of free-living populations of +_Pseudemys scripta_ showed that growth-rings, once formed, did not +change in size, that the area between any two major growth-rings +represented one season of growth, and that growth-rings were reliable +indicators of age as long as the impression of the areola remained on +the scutes studied. Cagle noted decreasing distinctness of +growth-rings after each molt. + +The relative lengths of the abdominal lamina and the plastron remain +approximately the same throughout life in _T. ornata_. Measurements +were made of the plastron, carapace, and abdominal lamina in 103 +specimens of _T. o. ornata_ from Kansas and neighboring states. The +series of specimens was divided into five nearly equal groups +according to length of carapace. Table 3 summarizes the relationship +of abdominal length to plastral length, and of carapace length to +plastral length. The mathematical mean of the ratio, abdominal +length/plastral length, in each of the four groups of larger-sized +turtles, was not significantly different from the same ratio in the +hatchling group. The relative lengths of carapace and plastron are not +so constant; the carapace is usually longer than the plastron in +hatchlings and juveniles, but shorter than the plastron in adults, +especially adult females. + + + TABLE 3.--The Relationship of Length of Abdominal Scute to + Plastral Length, and of Plastral Length to Length of Carapace, + in 103 Specimens of _T. o. ornata_ Arranged in Five Groups + According to Length of Carapace. The Relative Lengths of + Abdominal Scute and Plastron are not Significantly Different in + the Five Groups. The Plastron Tends to be Longer than the + Carapace in Specimens of Adult or Nearly Adult Size. + ===============+=========+===========================+================== + | | Length of abdominal |Individuals having + | | as a percentage of | plastron longer + LENGTH | Number | length of plastron | than carapace + OF CARAPACE | of | | + |specimens|----------------+----------+------+----------- + | |Mean A+-[sigma]m | Extremes |Number|Percentage + ---------------+---------+----------------+----------+------+----------- + Less than | | | | | + 50 mm. | 23 | 18.3A+-.498 |13.7-20.3 | 7 | 38.5 + (Juveniles) | | | | | + ---------------+---------+----------------+----------+------+----------- + 50 to 69 mm. | 20 | 17.8A+-.303 |15.2-20.2 | 8 | 40.0 + (Juveniles) | | | | | + ---------------+---------+----------------+----------+------+----------- + 70 to 100 mm. | 20 | 17.9A+-.445 |14.3-20.6 | 15 | 75.0 + (Subadults) | | | | | + ---------------+---------+----------------+----------+------+----------- + More than | | | | | + 100 mm. | 20 | 17.8A+-.236 |16.4-20.6 | 13 | 65.0 + (Adult males) | | | | | + ---------------+---------+----------------+----------+------+----------- + More than | | | | | + 100 mm. | 20 | 18.8A+-.510 |15.1-25.7 | 19 | 95.0 + (Adult females)| | | | | + ---------------+---------+----------------+----------+------+----------- + + +The length of any growth-ring on the abdominal lamina can be used to +determine the approximate length of the plastron at the time the +growth-ring was formed. Actual and relative increases in length of the +plastron can be determined in a like manner. For example, a +seven-year-old juvenile (KU 3283) with a plastron 74.0 millimeters +long had abdominal growth-rings (beginning with areola and ending with +the actual length of the abdominal) 5.9, 7.8, 9.5, 10.7, 12.0, 12.5, +14.3, and 14.9 millimeters long. Using the + + [AB ABA¹] +proportion, [-- = -- ], where AB is the abdominal length, PL the + [PL X ] + +plastral length, ABA¹ the length of any given growth-ring, and X the +plastral length at the time growth-ring ABA¹ was formed, the plastral +length of this individual was 29.3 millimeters at hatching, 38.8 at +the end of the first full season of growth, and 47.2, 53.2, 59.6, +62.1, and 71.0 millimeters at the end of the first, second, third, +fourth, fifth, and sixth seasons of growth, respectively. The present +length of the abdominal (14.9 mm.) indicates an increment of three +millimeters in plastral length in the seventh season, up to the time +the turtle was killed (June 25). This method of studying growth in +turtles was first used by Sergeev (1937) and later more extensively +used by Cagle (1946 and 1948) in his researches on _Pseudemys +scripta_. Because the plastron is curved, no straight-line measurement +of it or its parts can express true length. Cagle (1946 and 1948) +minimized error by expressing plastral length as the sum of the +laminal (or growth-ring) lengths. This method was not possible in the +present study because growth-rings on parts of one or more laminae +(chiefly the gulars and anals) were usually obliterated by wear, even +in young specimens. It was necessary to express plastral length as the +sum of the lengths of forelobe and hind lobe. + +The abdominal lamina was selected for study because of its length +(second longest lamina of plastron), greater symmetry, and flattened +form. Although the abdominal is probably subject to greater, over-all +wear than any other lamina of the shell, wear is even, not localized +as it is on the gulars and anals. + +In instances where some of the growth-rings on an abdominal lamina +were worn but other rings remained distinct, reference to other, less +worn lamina permitted a correct interpretation of indistinct rings. + +Abdominal laminae were measured at the interlaminal seam; since the +laminae frequently did not meet perfectly along the midline (and were +of unequal length), the right abdominal was measured in all specimens. +Growth-rings on the abdominal laminae were measured in the manner +shown in Plate 22. + +Data were obtained for an aggregate of 1272 seasons of growth in 154 +specimens (67 females, 48 males, and 39 of undetermined sex, chiefly +juveniles). Averages of calculated plastral length were computed in +each year of growth for specimens of known sex (Figs. 9 and 10) and +again for all specimens examined. Annual increment in plastral length +was expressed as a percentage of plastral length at the end of the +previous growing season (Fig. 11). Increment in plastral length for +the first season of growth was expressed as a percentage of original +plastral length because of variability of growth in the season of +hatching; growth increments in the season following hatching are, +therefore, not so great as indicated in Figure 11. + + +Growth of Juveniles + +Areas of new laminal growth were discernible on laboratory hatchlings +soon after they ate regularly. Hatchlings that refused to eat or that +were experimentally starved did not grow. The first zone of epidermis +was separated from the areola by an indistinct growth-ring (resembling +a minor growth-ring) in most hatchlings, but in a few specimens the +new epidermis appeared to be a continuation of the areola. Major +growth-rings never formed before the onset of the first hibernation. + +Growth in the season of hatching seems to depend on early hatching and +early emergence from the nest. Under favorable conditions hatchlings +would be able to feed and grow eight weeks or more before +hibernation. Hatchlings that emerge in late autumn or that remain in +the nest until spring are probably unable to find enough food to +sustain growth. + +Sixty-four (42 per cent) of the 154 specimens examined showed +measurable growth in the season of hatching. The amount of increment +was determined in 36 specimens having a first growth-ring and an +areola that could be measured accurately. The average increment of +plastral length was 17.5 per cent (extremes, 1.8-66.0 per cent) of the +original plastral length. Ten individuals showed an increment of more +than 20 per cent; the majority of these individuals (8) were hatched +in the years 1947-50, inclusive. + + [Illustration: FIG. 9. See legend for Fig. 10.] + + [Illustration: FIG. 10. The relationship of size to age in + _T. o. ornata_, based on studies of growth-rings in 115 + specimens of known sex (67 females and 48 males) from eastern + Kansas. Size is expressed as plastral length at the end of each + growing season (excluding the year of hatching) through the + twelfth and thirteenth years (for males and females, + respectively) of life. Vertical and horizontal lines represent, + respectively, the range and mean. Open and solid rectangles + represent one standard deviation and two standard errors of the + mean, respectively. Age is expressed in years.] + +Some hatchlings that grow rapidly before the first winter are as large +as one- or two-year-old turtles, or even larger, by the following +summer. Individuals that grew rapidly in the season of hatching tended +also to grow more rapidly than usual in subsequent seasons; 80 per +cent of the individuals that increased in plastral length by 20 per +cent or more in the season of hatching, grew faster than average in +the two seasons following hatching. Early hatching and precocious +development presumably confer an advantage on the individual, since +turtles that grow rapidly are able better to compete with smaller +individuals of the same age. Theoretically, turtles growing more +rapidly than usual in the first two or three years of life, even if +they grew subsequently at an average rate, would attain adult size and +sexual maturity one or more years before other turtles of the same +age. A few turtles (chiefly males) attain adult size (and presumably +become sexually mature) by the end of the fifth full season of growth +(Figs. 9 and 10). These individuals, reaching adult size some three to +four years sooner than the average age, were precocious also in the +earlier stages of postnatal development. + +Young box turtles reared in the laboratory grew more slowly than +turtles of comparable ages under natural conditions; this was +especially evident in hatchlings and one-year-old specimens. Slower +growth of captives was caused probably by the unnatural environment of +the laboratory. Captive juveniles showed a steady increase in weight +(average, .52 grams per ten days) as they grew whereas captive +hatchlings tended to lose weight whether they grew or not. + + +Growth in Later Life + +After the first year growth is variable and size is of little value as +an indicator of age. Although in the turtles sampled variation in size +was great in those of the same age, average size was successively +greater in each year up to the twelfth and thirteenth years (for males +and females, respectively), after which the samples were too small to +consider mathematically. + +Increments in plastral length averaged 68.1 per cent in the year after +hatching, 28.6 per cent in the second year and 18.1 per cent in the +third year. From the fourth to the fourteenth year the growth-rate +slowed gradually from 13.3 to about three per cent (Fig. 11). These +averages are based on all the specimens examined (with no distinction +as to sex); they give a general, over-all picture of growth rate but +do not reflect the changes that occur in growth rate at puberty (as +shown in Figs. 9 and 10). + +Rate of growth and, ultimately, size are influenced by the attainment +of sexual maturity. Adult females grow larger than adult males. Males, +nevertheless, grow faster than females and become sexually mature when +smaller and younger. Examination of gonads showed 17 per cent of the +males to be mature at plastral lengths of 90 to 99 millimeters, 76 per +cent at 100 to 109 millimeters, and 100 per cent at 110 millimeters, +whereas the corresponding percentages of mature females in the same +size groups were: zero per cent, 47 per cent, and 66 per cent. Of the +females, 97 per cent were mature at 120 to 129 millimeters and all +were mature at 130 millimeters (Fig. 13). Because growth slows +perceptibly at sexual maturity, it is possible, by examination of +growth-rings, to estimate the age of puberty in mature specimens. + +[Illustration: FIG. 11. Average increment in plastral length +(expressed as a percentage of plastral length at the end of the +previous season of growth) in the season of hatching (H) and in each +of the following 14 years of life, based on 1073 growth-rings. The +number of specimens examined for each year of growth is shown in +parentheses. Records for males and females are combined.] + +Attainment of sexual maturity, in the population studied, was more +closely correlated with size than with age. For example, nearly all +males were mature when the plastron was 100 to 110 millimeters long, +regardless of the age at which this size was attained. The smallest +mature male had a plastral length of 99 millimeters; according to the +data presented in Figures 9 and 10, therefore, a few males reach +sexual maturity in the fourth year, and increasingly larger portions +of the population become mature in the fifth, sixth, and seventh +years. The majority become mature in the eighth and ninth years. +Likewise, females (smallest mature specimen, 107 mm.) may be sexually +mature at the end of the sixth year but most of them mature in the +tenth and eleventh years. + +Annual Period of Growth + +In growing individuals, narrow zones of new epidermis form on the +laminae in spring. Nearly all the growing individuals collected in May +of 1954 and 1955 had zones of new epidermis on the shell but those +collected in April did not. Activity in the first week or two after +spring emergence is sporadic and regular feeding may not begin until +early May. Once begun, growth is more or less continuous as long as +environmental conditions permit foraging. The formation of minor +growth-rings and adjacent growth-zones in autumn, provides evidence +that growth commonly continues up to the time of hibernation. The +number of growing days per year varies, of course, with the +favorableness of environmental conditions. The length of time (162 +days) given by Fitch (1956b:438) as the average annual period of +activity for _T. ornata_ is a good estimate of the number of growing +days per season. + + +Environmental Factors Influencing Growth + +Zones of epidermis formed in some years are wider or narrower than the +zones bordering them (Pl. 22). Zones notably narrower or wider than +the average, formed in certain years, constituted distinct landmarks +in the growth-histories of nearly all specimens; for example, turtles +of all ages grew faster than average in 1954 and zones of epidermis +formed in this year were always wider than those formed in 1953 and +1955. + +An index to the relative success of growth in each calendar year was +derived. Records of growth for all specimens in each age group were +averaged; the figure obtained was used to represent "normal" or +average growth rate in each year of life (Fig. 12). The over-all +averages for the various age groups were then compared with records of +growth attained by individuals of corresponding age in each calendar +year, growth in a particular year being expressed as a percentage of +the over-all average. The percentages of average growth for all ages +in each calendar year were then averaged; the mean expressed the +departure from normal rate of growth for all turtles growing in a +particular calendar year. For example, the over-all average increment +in plastral length in the fifth year of life was 12.1 per cent, the +increment in the sixth year was 10 per cent, and so on (Fig. 11). In +1953, turtles in their fifth and sixth years increased in plastral +length by 11.4 and 9.1 per cent, or grew at 94.2 and 91.0 per cent of +the normal rate, respectively. The percentages of normal growth rate +for these age groups averaged with percentages of the other age groups +in 1953 revealed that turtles grew at approximately 86 per cent of the +normal rate in 1953. + +Growth rates were computed for the twelve-year period, 1943-1954, +because of the concentration of records in these years. Scattered +records also were available for many of the years from 1901-1942. +Records for individuals in the season of hatching and the first full +season of growth were not considered. + +Direct correlation exists between growth rate and average monthly +precipitation in the season of growth (April to September) (Fig. 12). +In nine of eleven years, the curve for growth rate followed the trend +of the curve for precipitation; but because other climatic conditions +also influenced growth, the fluctuations in the two curves were not +proportional to one another. + +Grasshoppers form an important element in the diet of box turtles. +Smith (1954) traced the relative abundance of grasshoppers over a +period of 100 years in Kansas, and this information is of significance +for comparison with data concerning growth of box turtles. In general, +the growth index was higher when favorable weather and large +populations of grasshoppers occurred in the same year. + +In the following summary, the numbers (1 to 5) used to express the +relative abundance of grasshoppers are from Smith (_op. cit._). Maxima +and minima refer to the twelve-year period, 1943-1954. The growth +index for each year (shown as a graph in Fig. 12) appears in brackets +and indicates the percentage of normal growth attained by all turtles +in that year. + +_Years Favorable for Growth_ + +=1954= [126.3]: Growth was better than average for turtles of all +ages. Grasshopper populations were highest (4+) since 1948. +Continuously warm weather, beginning in the last few days of March, +permitted emergence in the first week of April; thereafter conditions +were more or less continuously favorable for activity until late +October. Although there was less than an inch of precipitation in +September, precipitation in August and October was approximately twice +normal and more or less evenly distributed. Warm weather in early +November permitted an additional two weeks of activity. + +=1945= [125.5]: This was the second most favorable year for growth and +the second wettest year. Records of growth are all from young turtles +(one to four years old), all of which grew more than average. Daily +maximum temperatures higher than 60 degrees Fahrenheit on 18 of the +last 19 days of March, combined with twice the normal amount of +precipitation in the same period, stimulated early emergence. August +and October were both dry (each with less than one inch of +precipitation) but diurnal temperatures remained warm through the +first week in November and probably prolonged activity of box turtles +at least until then. Grasshoppers were more abundant (3.7) than +normal. + +_Years Unfavorable for Growth_ + +=1944= [83.1]: This was the poorest growing year for the period +considered. The lack of a continuously warm, wet period in early +spring probably delayed emergence until the last week in April. +Temperatures remained warm enough for activity until early November, +but dry weather in September and October probably curtailed activity +for inducing long periods of quiescence; most of the precipitation +that occurred in the latter two months fell in a one-week period +beginning in the last few days of September. Grasshopper populations +were higher (4.0) than normal. + +=1953= [85.6]: This was the second poorest growing year and the driest +year in the period considered. Intermittently cold weather in spring +delayed emergence until the last week in April when nearly an inch of +rain fell. Temperatures were higher than normal from June to October. +The period from September to the end of October was dry and the small +amount of precipitation that occurred was concentrated chiefly at the +beginning and end of that period. Temperatures in late October and +early November were lower than normal. Grasshopper populations were +low (2.2). + +=1952= [88.3]: Environmental conditions were poor for growth and much +like the conditions described for 1953. In both years growth was much +less than normal in turtles of all ages except for one group (adults +that were 10 and 11 years old in 1952 and 1953, respectively) that was +slightly below normal in 1952 and slightly above normal in 1953. + +The small number of records for 1955 were not considered in Figure +12. Warm weather in the last half of March lengthened the growing +season, and environmental conditions, as in 1954, were more or less +favorable throughout the rest of the summer; 1955 probably ranks with +1954 as an exceptionally good year for growth of box turtles. + +Although the number of records available for turtles hatched in the +period from 1950 to 1954 is small, a few records are available for all +these years except 1951. In general, small samples of turtles hatched +in these years reflect only the difficulty of collecting hatchlings +and juveniles. In 1951, conditions for incubation and hatching were +poor and the lack of records for that year actually represents a high +rate of prenatal and postnatal mortality. Rainfall in the nesting +season was two to three times normal and temperatures were below +normal. Flooding occurred in low areas of Douglas County and many eggs +may have been destroyed when nests were inundated. Cold weather +probably increased the time of incubation for surviving eggs so that +only a few turtles could hatch before winter. Flooding and cold, wet +weather in the season of growth and reproduction, affecting primarily +eggs and hatchlings, may act as checks on populations of _T. ornata_ +in certain years. + + [Illustration: FIG. 12. The relation of growth rate in + _Terrapene o. ornata_ (solid line) to precipitation (dotted + line) in eastern Kansas. "Normal" rate of growth was determined + by averaging records of increase in length of plastron for + turtles in each age group. The growth index is expressed as a + percentage of normal growth and is the mean departure from + normal of all age groups in each calendar year. Precipitation + is for the period, April to September (inclusive), at Lawrence, + Douglas Co., Kansas. The means for precipitation (4.3) and + growth index (100) are indicated by horizontal lines at the + right of the graph.] + +The environmental factors governing activity of terrestrial turtles +seem to differ at least in respect to threshold, from the factors +influencing the activity of aquatic turtles. A single month that was +drier or cooler than normal probably would not noticeably affect +growth and activity of aquatic emyids in northeast Kansas, but might +greatly curtail growth of box turtles. + +Cagle (1948:202) found that growth of slider turtles (_Pseudemys +scripta_) in Illinois paralleled the growth of bass and bluegills in +the same lake; in the two years in which the fish grew rapidly, the +turtles did also, owing, he thought to "lessened total population +pressure" and "reduced competition for food." Growth of five-lined +skinks (_Eumeces fasciatus_) on the Natural History Reservation +paralleled growth of box turtles, probably because at least some of +the same environmental factors influence the growth of both species. +Calculations of departure from normal growth in _E. fasciatus_, made +by me from Fitch's graph (1954:84, Fig. 13), show that relative +success of growth in the period he considered can be ranked by year, +in descending order, as: 1951, 1949, 1948, 1950, 1952. This +corresponds closely to the sequence, 1951, 1948, 1949, 1950, 1952, for +_T. ornata_. + + +Number of Growing Years + +Growth almost stops after the thirteenth year in females and after the +eleventh or twelfth year in males, approximately three years, on the +average, after sexual maturity is attained. The oldest individuals in +which plastral length had increased measurably in the season of +capture were females 14 (2 specimens) and 15 (1) years old. The age of +the oldest growing male was 13 years. + +The germinal layer of the epidermis probably remains semiactive +throughout life but functions chiefly as a repair mechanism in adults +that are no longer growing. Growth-rings continue to form irregularly +in some older adults. Growth-rings formed after the period of regular +growth are so closely approximated that they are unmeasurable and +frequently indistinguishable to the unaided eye. If the continued +formation of growth-rings is not accompanied by wear at the edges of +the laminae, the laminae meeting at an interlaminal seam descend, like +steps, into the seam (Pl. 22, Fig. 2). Interlaminal seams of the +plastron deepen with advancing age in most individuals. + +Some individuals that are well past the age of regular growth show +measurable increments in years when conditions are especially +favorable. The three oldest growing females were collected in 1954--an +exceptionally good year for growth. Allowing some latitude for +irregular periods of growth in favorable years subsequent to the +period of regular, more or less steady growth, 15 to 20 years is a +tenable estimate of the total growing period. + +Longevity + +Practically nothing is known about longevity in _T. ornata_ or in +other species of _Terrapene_ although the several plausible records of +ages of 80 to more than 100 years for _T. carolina_ (Oliver, +1955:295-6) would indicate that box turtles, as a group, are +long-lived. There is no known way to determine accurately the age of +an adult turtle after it has stopped growing. It was possible +occasionally to determine ages of 20 to 30 years with fair accuracy by +counting all growth-rings (including those crowded into the +interabdominal seam) of specimens having unworn shells. Without the +presence of newly formed epidermis as a landmark, however, it was +never certain how many years had passed since the last ring was +formed. + + [Illustration: FIG. 13. The relationship of sexual maturity to + size in 164 specimens (94 females and 70 males) of _Terrapene + o. ornata_, expressed as the percentage of mature individuals + in each of five groups arranged according to plastral length. + Sexual maturity was determined by examination of gonads. Solid + bars are for males and open bars for females. The bar for males + in the largest group is based on assumption since no males in + the sample were so long as 130 mm. Males mature at a smaller + size and lesser age (see also Figs. 9 and 10) than females. + Plastral lengths of the smallest sexually mature male and + female in the sample were, respectively, 99 and 107 mm.] + +Mattox (1936) studied annual rings in the long bones of painted +turtles (_Chrysemys picta_) and found fewer rings in younger than in +older individuals but, beyond this, reached no important conclusion. +In the present study, thin sections were ground from the humeri and +femurs of box turtles of various ages and sizes; the results of this +investigation were negative. Distinct rings were present in the +compact bony tissue but it appeared that, after the first year or two, +the rings were destroyed by encroachment of the marrow cavity at about +the same rate at which they were formed peripherally. + +The only methods that I know of to determine successfully the +longevity of long-lived reptiles would be to keep individuals under +observation for long periods of time or to study populations of marked +individuals. Both methods have the obvious disadvantage of requiring +somewhat more than a human lifetime to carry them to completion. +Restudy, after one or more decades, of the populations of turtles +marked by Fitch and myself may provide valuable data on the average +and maximum age reached by _T. ornata_. + +Ornate box turtles probably live at least twice as long as the total +period of growing years. An estimated longevity of 50 years would seem +to agree with present scant information on age. Considering +environmental hazards, it would be unusual for an individual to +survive as long as 100 years in the wild. + + +Weight + +Weights of ornate box turtles varied so much that no attempt was made +to correlate weight with size. Absolute weights have little +significance since weight is affected to a large extent by the amount +of fluid in the body. Turtles that had recently imbibed were naturally +heavier than those that had not; turtles brought to the laboratory and +kept there for several days lost weight by evaporation and by voiding +water. Weights of 22 adult females (53 records) and 10 adult males (22 +records) averaged 391 and 353 grams respectively, in the period from +September, 1954, to October, 1956. Females characteristically gained +weight in spring and early summer and were lighter after nesting. +Turtles of both sexes gained weight in September and October. + + +Bony Shell + +_Fontanelles_ + +At the time of hatching, fontanelles remain where bones of the shell +have not yet articulated with their neighbors. In general, the +fontanelles of the shell are closed by the time sexual maturity is +attained, but some remain open a year or two longer. + +The fontanelles of the shell are classified as follows (see Figs. 14 +to 16 and 18 to 19): + +_Plastron_ + +1.) _Anteromedian._ Rhomboidal; limited anteriorly by hyoplastral +bones and posteriorly by hypoplastral bones; posterior tip of +entoplastral bone may project into this fontanelle. + +2.) _Posteromedian._ Limited anteriorly by hypoplastral bones and +posteriorly by xiphyplastral bones (since hypoplastral bones do not +articulate medially in hatchlings, anteromedian and posteromedian +fontanelles form a single, more or less dumbbell-shaped opening). + + [Illustration: FIG. 14. Extent of closure of the + costoperipheral fontanelles in relation to length of plastron + in 17 skeletons of _T. o. ornata_ from eastern Kansas. Extent + of closure is expressed as an estimated percentage of total + closure of all the costoperipheral fontanelles, even though + some of them close sooner than others. Closure is usually + complete by the time sexual maturity is attained.] + + +_Carapace_ + +1.) _Costoperipheral._ Openings between the free ends of developing +ribs, between nuchal bone and first rib, and, between pygal bone and +last rib; limited laterally by peripheral bones; variable in shape. + +2.) _Costoneural._ Triangular openings on either side of middorsal +line between proximal ends of costal plates and developing neural +plates. + +The costoneural fontanelles are nearly closed in individuals of the 70 +millimeter (plastron length) class and seldom remain open after a +length of 80 millimeters is attained (Fig. 14). Of the costoperipheral +fontanelles, the anterior one (between first rib and nuchal bone) +closes first and the posterior one (between last rib and pygal bone) +last. It remains open in some turtles in which the plastron is longer +than 100 millimeters. The remaining costoperipheral fontanelles close +in varying sequence but those in the area of the bridge (nos. 2 to 5), +where there is presumably greater stress on the shell, close sooner +than the others. + +The plastral fontanelles are closed in most specimens of the 90 +millimeter (plastron length) class; the anteromedian fontanelle closes +first. + +The meager covering of the fontanelles makes juvenal turtles more +susceptible than adults to many kinds of injuries and to predation. + +_Movable Parts of the Shell_ + +Parts of the shell that are more or less movable upon one another and +that function in closing the shell are found in several families of +Recent turtles. African side-necked terrapins of the genus _Pelusios_ +have a movable forelobe on the plastron. Kinosternids have one or two +flexible transverse hinges on the plastron. In the Testudinidae the +African _Kinixys_ has a movable hinge on the posterior part of the +carapace and _Pyxis arachnoides_ of Madagascar has a short, hinged, +anterior plastral lobe. Certain trionychid turtles, such as +_Lissemys_, utilize the flexible flaps of the carapace (the flaps of +some species are reinforced with peripheral bones) to close the shell. + +Movable shell-parts of turtles are, in general, protective in +function; they cover parts of the soft anatomy that would otherwise be +exposed. + +A hinged plastron, capable of wholly or partly closing the shell, +occurs in six genera of the family Emyidae (see introduction). In +these emyids the plastron is divided into two lobes, which are joined +to each other by ligamentous tissue at the junction of the hyoplastral +and hypoplastral bones; externally, the hinge occurs along the seam +between the pectoral and abdominal laminae. This junction forms a more +or less freely movable hinge in adults. The plastron is attached to +the carapace by ligamentous tissue. Both lobes of the plastron or only +the buttresses of the hind lobe may articulate with the carapace. The +former condition obtains in _Emys_ and _Emydoidea_; the latter more +specialized condition is found in _Terrapene_. + +In generalized emyid turtles such as _Clemmys_ there are no movable +shell parts. The plastron is joined to the carapace by the sutures of +the bridge. A long stout process, the axillary buttress, arises on +each side from the hyoplastron and articulates with the tip of the +first costal. A similar process, the inguinal buttress, arises from +the anterior part of each of the hypoplastral elements and meets the +sixth costal on each side. The buttresses form the anterior and +posterior margins of the bridge. It is clear that movement of the +plastron in many emyids is mechanically impossible because of the +bracing effect of the buttresses. + +In _Terrapene_ the movable articulations of the shell are neither +structurally nor functionally developed in juveniles. Adults of _T. +ornata_ have highly modified bony buttresses on the plastron that are +homologous with those in more generalized emyids. The inguinal +buttresses are low and wide, and have a sheer lateral surface forming +a sliding articulation with the fifth and sixth peripheral bones of +the carapace. The axillary buttresses are reduced to mere bony points +near the posterolateral corners of the forelobe and do not articulate +directly with the carapace (Figs. 15 and 16). + +The fifth peripheral bone, constituting the lowest point of the +carapace, has a medial projection that acts as a pivoting point for +both lobes of the plastron; the roughened anterior corners of the hind +lobe articulate with these processes. The roughened posterior corners +of the forelobe of the plastron likewise articulate with these +processes. The posterior process or "tail" of the entoplastron extends +to, or nearly to, the bony transverse hinge. + +In juveniles that have been cleared and stained, the homologues of the +parts that are movable in adults are easily identifiable; the +proportions of these parts and their relations to one another are, +however, much different. + +In juveniles (Figs. 18 and 19) the buttresses are relatively longer +and narrower, and are distinct--more nearly like those of generalized +emyids than those of adult _T. ornata_. The buttresses enclose a large +open space, which in adults is filled by the fifth peripheral. The +hyoplastral and hypoplastral bones are in contact only laterally. They +are firmly joined by bony processes; the interdigitating nature of +this articulation contrasts with its homologue in the adult, the point +where the roughened corners of the forelobes and hind lobes meet. The +fifth peripheral in juveniles (Fig. 19) lies dorsal to this +articulation. The position of the future transverse hinge corresponds +to a line passing through the articulations of the hyoplastra and +hypoplastra. The tail of the entoplastron ordinarily extends posterior +to this line in juveniles. + + [Illustration: FIG. 15. Lateral view of adult shell (A-- A3/4), + showing movable parts with anterior portion at left. + (Abbreviations are as follows: ab, axillary buttress; + hp, hypoplastron; hy, hyoplastron; ib, inguinal buttress; + p5, fifth peripheral bone; th, transverse hinge).] + + [Illustration: FIG. 16. Medial view of adult shell (A-- A3/4), + showing movable parts with anterior portion at left. + (Abbreviations as in fig. 15).] + + [Illustration: FIG. 17. Lateral view of adult shell (A-- A3/4), + showing scutellation of movable parts with anterior portion at + left. (Abbreviations are as follows: ap, apical scale; ax, + axillary scale; m5, fifth marginal scale; pl, pectoral + lamina.)] + +The external scutellation of the plastral hinge in adults also differs +from that in juveniles. In adults (Fig. 17 and Pl. 8) the transverse +hinge is marked by ligamentous tissue between the pectoral and +abdominal laminae; the forelobe of the plastron is distinctly narrower +than the hind lobe. Two small scales lie near the corner of the hinge +on each side. The larger and more anterior of these scales is the +axillary; it is present in box turtles of all ages. The smaller scale +(Fig. 17), to my knowledge, has never been named or mentioned in the +literature; it is herein termed the apical scale. It is a constant +feature in adults but is always lacking in hatchlings and small +juveniles. Other scales, much smaller than the axillary and apical, +occur on the ligamentous tissue of the hinge of some adults. + + [Illustration: FIG. 18. Plastron of hatchling (A-- 2), cleared + and stained to show bony structure. (Abbreviations not listed + in legend for Fig. 15 are as follows: af, anteromedian + fontanelle; ep, epiplastron; pf, posteromedian fontanelle.)] + + [Illustration: FIG. 19. Carapace of hatchling (A-- 1A1/2), + cleared and stained to show bony structure; lateral view; + anterior end at left. (Abbreviations as in Fig. 15.)] + + [Illustration: FIG. 20. Lateral view of hatchling (A-- 1); note + the lateral process of the pectoral lamina (pl) extending + posterior to the axillary scale (ax) in a position + corresponding to the apical scale of adults. There is no + external indication of the transverse hinge in young + individuals. The yolk sac of this individual has been retracted + but the umbilicus (umb) has not yet closed.] + +In juveniles (Fig. 20) the pectoroabdominal seam contains no +ligamentous tissue and is like the other interlaminal seams of the +plastron. A lateral apex of the pectoral lamina projects upward behind +the axillary scale on each side, in the position occupied by the +apical scale of adults. Examination of a large series of specimens +revealed that the apical scale of adults becomes separated from the +lateral apex of the pectoral lamina at approximately the time when the +hinge becomes functional as such. + +Ontogenetic changes in the shell can be summarized as follows: 1) +Buttresses become less distinct in the first two years of life +(plastral lengths of 40 to 55 mm.); 2) Interdigitating processes of +the forelobes and hind lobes become relatively shorter and wider, the +entoplastron no longer projects posterior to the hinge, the lateral +apex of the pectoral lamina becomes creased, and some movement of the +plastron can take place between the second and third years (plastral +lengths of 55 to 65 mm.); 3) Plastral lobes become freely movable upon +one another and upon the carapace by the end of the fourth year +(plastral length approximately 70 mm.) in most individuals. + +The plastron of a juvenal box turtle is not completely immovable. The +bones of the shell are flexible for a time after hatching and allow +some movement of the plastron; but the relatively greater bulk of the +body in young box turtles would prevent complete closure of the shell +even if a functional hinge were present. Hatchlings can withdraw the +head and forelegs only to a line running between the anterior edges of +the shell. To do so the rear half of the shell is opened and the hind +legs are extended. When the head and forelegs are retracted to the +maximum, the elbow-joints are pressed against the tympanic region or +behind the head; the fore-limbs cannot be drawn part way across the +snout, as in adults. Hatchlings can elevate the plastron to an angle +of approximately nine degrees; the plastron of an adult, with shell +closed, is elevated about 50 degrees. Hatchlings flex the plastron +chiefly in the region of the humeropectoral seam, rather than at the +anlage of the transverse hinge. + +Adult box turtles, when walking, characteristically carry the forelobe +of the plastron slightly flexed. This flexion of the plastron, +combined with its naturally up-turned anterior edge, cause it to +function in the manner of a sled runner when the turtle is moving +forward. A movable plastron, therefore, in addition to its primarily +protective function, seems to aid the turtle in traveling through tall +grass or over uneven ground. The gular scutes, on the anterior edge of +the forelobe, become worn long before other plastral laminae do. + +An adult female from Richland County, Illinois, had an abnormal but +functional hinge on the humeropectoral seam in addition to a normal +hinge on the pectoroabdominal seam. The abnormal hinge resulted from a +transverse break in which ligamentous tissue later developed. The +muscles closing the plastron moved the more anterior of the two +hinges; the normal hinge was not functional. + + +Color and Markings + +The markings of the shell change first when postnatal growth begins +and again when sexual maturity is attained. They are modified +gradually thereafter as the shell becomes worn. + +In hatchlings the ground color ordinarily is dark brown but in some +individuals is paler brown or tan. Markings on the dark background are +pale yellow. Markings on the central and lateral scutes vary from a +regularly arranged series of well defined spots and a middorsal stripe +to a general scattering of small flecks. In some specimens the pale +markings of the carapace are faint or wanting. Lateral parts of +marginal scutes are always pale yellow and form a border around the +carapace. + +Close examination of the carapace of any hatchling shows the following +basic arrangement of markings: each lateral scute has a centrally +placed pale spot and four to seven smaller pale marks arranged around +the edge of the scute; each central scute has a central, longitudinal +mark and several (usually two, four, or six) smaller pale marks +arranged around the edge of the scute, chiefly the lateral edges (Pl. +23). Variations in pattern result when some or all of the markings +divide into two or more parts. + +By the end of the first full season of growth, the markings have a +radial pattern. At this stage, the markings of the areola, with the +exception of the central spot, are obscure. The radial marks, sharply +defined and straight-sided, appear only on the newly formed parts of +the epidermal laminae. Each radial mark originates opposite one of the +peripheral marks of the areola. Other radial marks are developed later +by bifurcation of the original radiations. + +The ground color of the plastron of hatchlings is cream-yellow, or +less often, bright yellow. The solid, dark brown markings on the +medial part of each lamina form a central dark area that contrasts +sharply with the pale background (Pl. 24). The soft tissue of the +navel is pale yellow or cream; when the navel closes, the dark +central mark of the plastron is unbroken except for thin, pale lines +along the interlaminal seams. + +When growth begins, the areas of newly formed epidermal tissue on the +anterior and medial borders of each areolar scute are pale. Wide, dark +radial marks, usually three per scute, appear on the newly formed +tissue. Subsequently, finer dark radiations appear between the three +original radiations. The wide radiations later bifurcate. By the time +adult or subadult size is reached, the plastron appears to have a +pattern of pale radiations on a _dark_ background. In general, the +markings of the plastron are less sharply defined than the markings of +the carapace (Pl. 24). + +There is a tendency for the dark markings of the plastron to encroach +on the lighter markings, if no wear on the shell occurs. However, as +the plastron becomes worn, the pale areas become more extensive and +the dark markings become broken and rounded. Severely worn plastra of +some old individuals lack dark markings. Wear on the carapace produces +the same general effect; but markings of the carapace, although they +may become blotched, are never obliterated in _Terrapene o. ornata_. + +The top of the head in most hatchlings is dark brown, approximately +the same shade as the ground color of the carapace; the part anterior +to the eyes is usually unmarked but a few individuals have a +semicircle of small pale spots over each eye or similar spots on much +of the head. The posterior part of the head is ordinarily flecked with +yellow. The skin on the top of the head, particularly between the +eyes, is roughened. The granular skin of the neck is grayish brown to +cream-yellow. There are one or two large pale spots behind the eye and +another pale spot at the corner of the mouth. Smaller, irregularly +arranged pale markings on the necks of some specimens form, with the +post-orbital and post-rictal spots, one or two short, ragged stripes. +The gular region is pale. + +In juveniles, the yellow markings of the head and neck are larger and +contrast more sharply with the dark ground color than in hatchlings. +Markings above the eyes, if present, fuse to form two pale, +semicircular stripes. In some older juveniles yellow marks on top of +the head blend with the dark background to produce an amber color. The +top of the neck darkens or develops blotches of darker color that +produce a mottled effect. Spots and stripes on the side of the neck +remain well defined. The skin on top of the head becomes smooth and +shiny. + +Adult females tend to retain the color and pattern of juveniles on the +head and neck although slight general darkening occurs with age. Many +adult females have the top of the head marked with bright yellow +spots. In adult males, the top and sides of the head, anterior to the +tympanum, are uniformly grayish green or bluish green; the mandibular +and maxillary beaks are brighter, yellowish green. Markings on the +head and neck of most adult males are obscure (Pl. 25) but the sides +of the neck remain mottled in some individuals. + +The antebrachium has large imbricated scales and _is_ distinctly set +off from the proximal part of the foreleg which is covered with +granular skin. The antebrachial scales of hatchlings are pale yellow; +each scale is bordered with darker color. General darkening of the +antebrachium occurs at puberty. In adult females each scale on the +anterior surface of the antebrachium is dark brown and has a +contrasting yellow, amber, or pale orange center. The anterior +antebrachial scales of adult males are dark brown to nearly black and +have bright orange or red centers. Old males have thickened +antebrachial scales. + +The iris of hatchlings and juveniles is flecked with yellow and brown; +the blending of these colors makes the eye appear yellow, golden, or +light brown when viewed without magnification. Adult females retain +the juvenal coloration of the eye; the iris of adult males is bright +orange or red. The work of Evans (1952) on _T. carolina_ suggests that +eye color in box turtles is under hormonal control. + + +Wear + +Presence or absence of areolae on laminae of the shell indicated +degree and sequence of wear. The anterior edges of carapace and +plastron, and the slightly elevated middorsal line (Pl. 23) wear +smooth in some individuals before the first period of hibernation. +Subsequent wear on the carapace proceeds posteriorly. For example, +turtles that retained the areola of the third central lamina, retained +also the areolae of the fourth and fifth centrals; when only one +central areola remained, it was the fifth. Lateral laminae wear in the +same general sequence. The areola of the fifth central lamina, because +of its protected position, persists in adult turtles that are well +past the age of regular growth. Areolae that are retained in some +older turtles are shed along with the epidermal layers formed in the +first year or two of life. Wear on the shell is probably correlated +with the habits of the individual turtle; smoothly-worn specimens +varied in size and age but were usually larger, older individuals. No +smoothly worn individual was still growing. + +Wear on the plastron is more evenly distributed than wear on the +carapace; wear is greatest on the lowest points of the plastron (the +gular laminae, the anterior portions of the anal laminae, and the +lateral edge of the tranverse hinge). + +The claws and the horny covering of the jaws are subject to greater +wear than any other part of the epidermis; presumably they continue to +grow throughout life. The occasional examples of hypertrophied beaks +and claws that were observed, chiefly in juveniles, were thought to +result from a continuous diet of soft food or prolonged activity on a +soft substrate. Ditmars (1934:44, Fig. 41) illustrated a specimen of +_T. carolina_, with hypertrophied maxillary beak and abnormally +elongate claws, that had been kept in a house for 27 years. + +The conformation of the maxillary beak in all species of _Terrapene_ +is influenced to a large extent by wear and is of limited value as a +taxonomic character. The beak of _T. ornata_ is slightly notched in +most individuals at the time of hatching and remains so throughout +life. The underlying premaxillary bone is always notched or +bicuspidate. The sides of the beak are more heavily developed than the +relatively thin central part. Normal wear on the beak maintains the +notch (or deepens it) in the form of an inverted U or V, much in the +manner of the bicrenate cutting edge on the grooved incisors of +certain rodents. In a series of 34 specimens of _T. ornata_ from +Kansas, selected at random from the K. U. collections, 92 per cent had +beaks that were "notched" to varying degrees, four per cent had hooked +(unnotched) beaks, and four per cent had beaks that were flat at the +tip (neither hooked nor notched). + + [Illustration: FIG. 21. Plantar views of right hind foot (male + at left, female at right) of _T. o. ornata_ (A-- 1), showing + sexual dimorphism in the shape and position of the first toe. + The widened, thickened, and inturned terminal phalanx on the + first toe of the male is used to grasp the female before and + during coitus.] + + + + +SEXUAL DIMORPHISM + + +Differences between adult males and females of _T. ornata_ have been +mentioned in several places in the preceding discussion of growth and +development. Several sexual characteristics--greater preanal length, +thickened base of the tail, slightly concave plastron, and smaller +bulk--are found also in males of many other kinds of emyid turtles. +From females, males of _T. ornata_ are most easily distinguished by +the bright colors of their eyes, heads, and antebrachial scales. An +additional, distinctive characteristic of males is the highly modified +hind foot. The first toe is greatly thickened and widened; when the +foot is extended, the first toe is held in a horizontal plane nearly +at right angles to the medial edge of the plantar surface (Fig. 21). +The hind foot of females is unmodified in this respect. Males tend to +have heavier, more muscular hind legs than females. + +The bright colors of males are maintained throughout the year and do +not become more intense in the breeding season. Males of _T. o. +luteola_ become melanistic in old age whereas males of the subspecies +_ornata_ do not. In old males of _luteola_ the skin becomes dark gray, +bluish, or nearly black and much of the bright orange or red of the +antebrachial scales and the green of the head is obliterated; the iris +may also darken but in most specimens it retains some red. Females of +_luteola_ tend also to darken somewhat in old age but not so much as +males; females of _ornata_ do not. Table 4 summarizes the more +important secondary sexual characters of _T. ornata_. + + + TABLE 4.--A Summary of Sexual Dimorphism in _Terrapene ornata_. + ============+============================+============================== + CHARACTER | MALES | FEMALES + ------------+----------------------------+------------------------------ + Head | Snout truncate in lateral | Snout relatively round in + | profile, top of head and | lateral profile; front of + | front of maxilliary beak | maxillary beak not forming + | forming an angle of nearly | right angle with top of head; + | 90A deg.; head yellowish green | head dark brown, distinct + | to bluish green; markings | pale markings on head and + | on head and neck reduced; | neck; head commonly spotted + | head never spotted dorsally| dorsally (Pl. 25, Figs. 5 + | (Pl. 11, Figs. 7 and 8). | and 6). + ------------+----------------------------+------------------------------ + Iris | Red | Yellowish brown + ------------+----------------------------+------------------------------ + Hind legs | Heavy and muscular; first | Not especially heavy or + | toe turned in, thickened, | muscular; first toe, if + | and widened (Fig. 21). | turned in, never thickened + | | or widened (Fig. 21). + ------------+----------------------------+----------------------------- + Forelegs | Centers of antebrachial | Centers of antebrachial + | scales bright orange or | scales yellow, pale orange, + | red. | or brown. + ------------+----------------------------+----------------------------- + Carapace | Relatively lower, length | Relatively higher, length + | contained in height (48 | contained in height (94 + | specimens) .58 times | specimens) .50 times + | (A+- .005[sigma]m, range, | (A+- .005[sigma]m, + | .50 to .69). | range .44 to .60). + ------------+----------------------------+------------------------------ + Plastron | Ordinarily slightly | Flat or convex, never + (hind lobe)| concave. | concave. + ------------+----------------------------+------------------------------ + + + + +TEMPERATURE RELATIONSHIPS + + +Tolerances to environmental temperatures, and reactions to thermal +stimuli influence the behavior of ectothermal animals to a large +extent. _Terrapene ornata_, like other terrestrial reptiles +inhabitating open grassland, is especially subject to the vicissitudes +of environmental temperature. Other species of turtles living in the +same area are more nearly aquatic and therefore live in a microhabitat +that is more stable as regards temperature. + +Approximately 500 temperature readings in the field and many others in +the laboratory were obtained from enough individuals to permit +interpretation of reactions involved in basking, in seeking cover, and +in emerging from temporary periods of quiescence at various times of +the day. + +Box turtles commonly used open places such as cow paths, ravines, and +wallows, for basking as well as for feeding and as routes of travel. +Burrows, dens beneath rocks, and forms, were used as shelter from high +and low temperatures as well as from predators. Determining whether a +turtle was truly active (moving about freely, feeding, or copulating), +was basking, or was seeking shelter was difficult because the turtle +sometimes reacted to the observer; for instance, basking turtles, +whose body temperatures were still suboptimum, might take cover when +surprised, and truly active turtles might remain motionless and appear +to be basking. By scanning open areas from a distance with binoculars, +an observer frequently could determine what turtles were doing without +disturbing them. In the final analysis of data, temperature records +accompanied by data insufficient to determine correctly the state of +activity of the turtle, were discarded, as were temperature records of +injured turtles and turtles in livetraps. + +Cowles and Bogert (1944:275-276) and Woodbury and Hardy (1948:177) +emphasized the influence of soil temperatures on body temperatures. It +is thought that air temperatures played a more important role than +soil temperatures in influencing body temperatures of _T. ornata_. +Soil temperatures were taken in the present study only when the turtle +was in a form, hibernaculum, or den. + + +Optimum Temperature + +Cowles and Bogert (1944:277) determined optimum levels of body +temperature of desert reptiles by averaging body temperatures falling +within the range of normal activity; they defined this range as, "... +extending from the resumption of ordinary routine [activity] ... to +... a point just below the level at which high temperatures drive the +animal to shelter." Fitch (1956b:439) considered optimum body +temperature in the several species that he studied to be near the +temperature recorded most frequently for "active" individuals; he +found (_loc. cit._) that of body temperatures of 55 active _T. +ornata_, 66 per cent were between 24 and 30 degrees, and that the +temperatures 27 and 28 occurred most frequently. Fitch concluded (_op. +cit._:473) that the probable optimum body temperature of _T. ornata_ +was 28 degrees and that temperatures from 24 to 30 degrees were +preferred. Although Fitch treated all non-torpid individuals that were +abroad in daytime as "active" and did not consider the phenomenon of +basking, his observations on optimum body temperature agree closely +with my own. + +Body temperatures of 153 box turtles that were known definitely to be +active, ranged from 15.3 to 35.3 degrees. The mean body temperature +for active turtles was 28.8 degrees (A+- 3.78[sigma]) (Fig. 22). +Ninety-two per cent of the temperatures were between 24 and 30 degrees +and 50 per cent were between 28 and 32; temperatures of 29 and 30 +degrees occurred most frequently (22 and 21 times, respectively). The +ten body temperatures below 24 degrees all were recorded before 9 A. +M. on overcast days when the air was cool and humid. It is noteworthy +that two of these low temperatures (18.8A deg. and 19.0A deg.) were from a +copulating pair of turtles; two others (21.8A deg. and 22.0A deg.) were from +individuals that were eating. The highest temperature (35.3A deg.) was from +a large female that was feeding at mid-morning in a partly shaded +area. + +The mean body temperature for active individuals (Fig. 22) is probably +somewhat below the ecological optimum, because a few temperatures were +abnormally low. The large number of body temperatures in the range of +29 to 31 degrees indicates an optimum closer to 30 degrees. Optimum +body temperatures may vary somewhat with the size, sex, or individual +preference of the turtle concerned. + + +Basking + +Although basking is common in terrestrial turtles, only a few authors +have mentioned it. Woodbury and Hardy (1948:177-178) did not use the +term in their account of thermal relationships in _Gopherus agassizi_; +their discussion indicates, however, that the tortoises move +alternately from sunny to shady areas to regulate body temperature. +Desert tortoises removed from hibernacula and placed in the sun warmed +to approximately 29.5 degrees before they became active, although a +few did so at temperatures as low as 15 degrees. According to Cagle +(1950:45), Sergeev (1939) studied body temperature and activity in the +Asiatic tortoise, _Testudo horsefieldi_, and found that individuals +basked for as much as two hours in the morning before beginning the +first activity of the day (feeding), but that tortoises did not bask +after a period of quiescense from late morning to late afternoon, +during which body temperatures were seemingly maintained nearer the +optimum than they were during nocturnal rest; body temperatures rose +to approximately 30 degrees before the tortoises became active. Since +body temperatures of 23 to 24 degrees were maintained at night, the +basking range of _Testudo horsefieldi_ may be considered to be +approximately 23 to 32 degrees. + +Ornate box turtles basked chiefly between sunrise and 10 or 11 A. M. +Body temperatures of 60 basking turtles ranged from 17.3 to 31.4 +degrees (mean, 25.5 A+- 3.08[sigma]). More than two-thirds (42) of these +body temperatures were higher than the air temperature near the +turtle, indicating probably that body temperature rises rapidly once +basking is begun. In the instances where body temperature was below +air temperature, the turtles had recently begun to bask (many were +known to have just emerged from forms or other cover where they had +spent the night) or were warming up more slowly because of reduced +sunlight. On cloudy days basking began later than on clear days and +body temperatures usually remained at a suboptimum level. Turtles that +basked on days that were cloudy and windy, or cold and windy, did so +in sheltered places, usually on the leeward sides of windbreaks such +as limestone rocks, rock fences, or ravine banks. It was evident in +these instances that the turtles either sought such shelter from the +wind or remained ensconced in the more complete shelter of a form or +burrow, not emerging at all. + +Open areas of various kinds were used as basking sites. Level +ground--such as on roads, cattle pathways, and bare areas surrounding +farm ponds--having unobstructed morning sunlight, nearby dense +vegetation, and choice opportunities for feeding (cow dung, mulberry +trees) was preferred. Basking was frequently combined with feeding; in +several instances box turtles were noted early in the morning at +suboptimum body temperatures eating grasshoppers, berries, or dung +insects. The predilection of box turtles for open areas is probably +important in permitting extended activity at suboptimum temperatures. +_T. ornata_ probably carries on more nearly normal activity on cool +days than do reptilian species with more sharply delimited thermal +tolerances. Collared lizards (_Crotaphytus collaris_), for example, +are chiefly inactive on days when the sky is overcast, although a few +individuals having suboptimum body temperatures can be found in open +situations (Fitch, 1956a:229 and 1956b:442). + + [Illustration: FIG. 22. The relationship of body temperature + (Centigrade) and kind of activity in _T. o. ornata_, compiled + from 355 field observations. Vertical and horizontal lines + represent, respectively, the range and mean. Open and solid + rectangles represent one standard deviation and two standard + errors of the mean, respectively.] + + +Toleration of Thermal Maxima and Minima + +The foregoing remarks on basking indicate the approximate, normal, +thermal tolerances of ornate box turtles. Many additional records of +body temperature were taken from turtles that were found under cover. +Turtles under cover in daylight were usually seeking protection from +either below-optimum or above-optimum temperatures. In avoiding low +temperatures, turtles usually chose more complete and permanent cover +than in avoiding high temperatures. + +Body temperatures of 64 box turtles that were seeking cover or that +were under cover because of high temperatures ranged from 28.9 to 35.8 +degrees (mean, 31.9 A+- 1.55[sigma]). Fifty-nine of these temperatures +(92 per cent) were 30 degrees or higher. Figure 22 shows this range to +overlap broadly with the temperature range of active turtles and the +means of the two groups are close to each other. Body temperatures +below 30 degrees (5) were all recorded late in the morning on hot +summer days when the air temperature was well above 30 degrees; they +are somewhat misleading because they are from turtles that were under +cover long enough to lower body temperature to the range of activity +although the turtles remained under cover because of hazardous +environmental temperatures. + +The commonest retreats used by box turtles to escape heat were burrows +of other animals and small dens under thick limestone rocks, where the +air remained cool, even in late afternoon. Most of the burrows and +dens on the Damm Farm were known to me and could be checked each day. +Turtles seeking temporary refuge from high temperatures +characteristically rested just inside the opening of a den or burrow. +Less frequently, turtles burrowed into ravine banks or just under the +sod on level ground. A number of individuals with above-optimum body +temperatures were found in the shade of trees or high weeds in early +afternoon on hot days. Mulberry trees provided ample shade for such +activity and, in June and July, when ripe mulberries were abundant on +the ground, turtles frequently fed on them at times of the day when +temperatures were more hazardous in other areas. + +Several turtles were found buried in mud or immersed in water at the +edges of ponds in the hottest part of the day; they were discovered at +first by accident and, on subsequent field trips by systematic +probing. Ordinarily the turtles were covered with mud or muddy water +and remained motionless, except for periodically raising the head to +the surface to breath. There was little vegetation near the edges of +ponds and by late morning on hot days the temperature of the +shallowest water was as high as the air temperature or higher. +Correspondingly, turtles found resting in mud and water had body +temperatures much higher than turtles in dens, burrows, or forms at +the same time of day. Box turtles that retreat to mud or shallow water +cool themselves less efficiently than they would in drier, better +protected microhabitats. I found no evidence that turtles went into +deeper water to cool themselves. + +The length of time spent under cover varied; most turtles had two +daily periods of activity, the second beginning in late afternoon. +Some turtles moved from shelter to shelter in the time between periods +of activity. Several turtles were known to remain quiescent +continuously for several days in the hottest part of the summer. + +The maximum temperature that a reptile can tolerate physiologically is +ordinarily higher than the maximum temperature tolerated voluntarily +(Cowles and Bogert, 1944:277); but, the two maxima may be separated by +only a few degrees. Most poikilothormous vertebrates neither tolerate +nor long survive body temperatures exceeding 40 degrees (Cowles and +Bogert, _op. cit._:269). + +It is evident (Fig. 22) that ornate box turtles do not often tolerate +body temperatures above 33 degrees and that temperatures in excess of +35 degrees are probably never tolerated under natural conditions. At +9:15 A. M. on July 5, 1955, an adult female emerged from mud where she +had spent the night (body temperature 28.4A deg., mud 28.4A deg., air 30A deg.). +After foraging for 40 minutes in bright sunlight on a grassy hillside +she had moved approximately 100 feet and her temperature had reached +34.6 degrees (air 33.0A deg.). At 9:56 A. M. she moved rapidly and directly +to a den under a rock nearby; 15 minutes later her body temperature +had not changed but after 65 minutes it had dropped to 33.4 degrees. +The temperature of air in the den was 31 degrees. This female began +her activities at nearly optimum body temperature relatively late in +the morning and, by foraging intensively for less than one hour, +probably was able nearly to satisfy her daily food requirements; by +foraging near suitable cover she could remain active until her body +temperature reached a critical threshold, and she thereby saved time +otherwise required for finding cover or making a form. + +The following observations, extracted from field notes, indicate that +body temperatures near 40 degrees are the approximate lethal maximum +and are well above those temperatures voluntarily tolerated by _T. +ornata_. On July 4, 1955, a subadult female was in the water at the +edge of a pond. The temperatures of the air, water, and turtle were +32.0, 30.6, and 30.2 degrees, respectively. At 11 A. M. the turtle was +tethered in direct sunlight on the hard-baked clay of the pond +embankment (temperature of air 33.4A deg.). The turtle's response to +steadily rising body temperature over a period of 31 minutes is +illustrated by the following notes. + + + Body + Time (A. M.) temperature Remarks + + 11:00 33.0 Tethered on slope. + + 11:05 34.6 Strains at tether in several directions. + + 11:09 36.5 Tries frantically to get away; draws in limbs and + head rapidly and momentarily at any movement on + my part, and hisses loudly. + + 11:13 37.5 Mouth held open slightly; turtle overturns in effort + to escape; frantic scrambling resumed a few seconds + after I right turtle. + + 11:17 38.2 Mouth now held open most of the time; white + froth begins to appear around mouth. + + 11:20 38.6 Stops activities every 10 seconds or so, rests chin + on ground and gapes widely; will still pull into + shell when prodded with stick. + + 11:23 39.2 Still wildly active; continues to gape widely every + few seconds. + + 11:27 39.4 Frothing at mouth profusely. + + 11:30 39.6 Attempts to escape are now in short feeble bursts. + + 11:31 Turtle released; crawls toward me and immediately + seeks shade of my body; when I move off, turtle + seeks shade of small isolated weed on pond embankment; + turtle removed to damp earth at edge + of pond. + + 11:35 39.5 Attempts to burrow into mud at edge of pond. + + 11:36 Enters shallow water and moves slowly back to + shore. + + 11:37 38.8 Turtle thrown into center of pond where it remains + motionless and drifts with wind to opposite + shore; remains inactive in mud and shallow water + at edge of pond; temperature of water near turtle + 35.5. + + 11:57 35.0 Moves 50 ft. up slope to shade of low vegetation. + + 01:55 P. M. 32.5 Turtle has not moved. + + +The overheating may have incapacitated the turtle since it moved only +50 feet in the next two days; its body temperatures on the two days +subsequent to the experiment were 26.8 and 20.6, respectively. + +The mentioned gaping, as in higher vertebrates generally, cools the +animal by evaporation from the moist surfaces of the mouth and +pharynx. By keeping the mouth open for more than a few minutes at a +time in hot dry weather, a turtle would surely lose body water in +amounts that could not always be easily replaced. Ornate box turtles +seem to utilize evaporation for cooling only in emergencies and rely +for the most part on radiation and conduction to lower body +temperature after reaching a relatively cool, dark retreat. + +Box turtles were never active at body temperatures below 15 degrees +and were seldom active at temperatures below 24 degrees. The two +lowest temperatures (15.3A deg. and 16.3A deg.) were taken from individuals +crossing roads on overcast days in early May. + +In 78 box turtles that were under cover because their environmental +temperatures were low, the body temperatures ranged from 2.7 to 30.6 +degrees (mean 19.8 A+- 6.38[sigma]). The range of body temperatures in +this group is greater than in the other groups shown in Figure 22 +because low body temperatures were studied over a wide range of +conditions, including hibernation. + +Box turtles actually seek cover because of low temperatures only in +fall and spring and on occasional unseasonable days in summer when +temperatures drop rapidly. Retreat to cover, in the normal cycle of +daily activity, is governed usually by high temperatures at mid-day or +by darkness at the end of the day. Turtles in dens, burrows, and grass +forms, tended to burrow if temperatures remained low for more than a +few hours. + +Box turtles under cover where they cannot bask have little control +over the lower range of body temperatures. The freezing temperatures +of winter can be escaped by burrowing deeper into the ground. +Temperatures approaching the lethal minimum, however, seldom occur +during the season of normal activity. By remaining hidden in a burrow +or den therefore, box turtles are fairly well protected from predators +but are at a thermal disadvantage. + +A number of turtles that had wet mud on their shells were found +basking in early morning near ditches, ponds, and marshy areas; +several others were partly buried in mud, shortly after daybreak, and +another was at the edge of a pond after dark. + +Eight adults, located just as they emerged from cover in early morning +on sunny days, had body temperatures of 19.7, 21.9, 24.2, 24.5, 25.8, +26.6, 28.7, and 29.5 degrees. In five emerging from earth forms, body +temperatures were at least a degree or two below the temperature of +the air; the other three came from mud or shallow water and had body +temperatures higher than the air temperature. + +Temperature is probably the primary stimulus governing emergence after +temporary periods of quiescence. Turtles in earthen forms are usually +completely covered or are head downward with only the hind quarters +exposed. Obviously, the more thoroughly a turtle protects itself +(beneath the insulating cover of a form, burrow, or den) against +unfavorable temperatures, the longer it will take for favorable +temperatures to bring about normal activity again. Turtles in forms +and deep burrows have a minimum of contact with the outer environment; +but in dens beneath rocks and in shallow burrows light and air can +enter freely. Turtles might be influenced in their activities to some +extent by the intensity of light at the opening of a burrow or den; +they are surely stimulated by changes in the temperature and humidity +of air coming through the opening. Shallow retreats that a turtle can +enter and leave with the least effort therefore seem most efficient +for purposes of thermocontrol, especially when they provide earthen +surfaces into which the turtles can burrow more deeply if more severe +environmental conditions develop. + +In October, 1955, nine _T. ornata_ of various sizes, collected in +Douglas County, Kansas, were brought to the laboratory for observation +under conditions of controlled temperature. They were kept at room +temperature for several days and were fed regularly, with the +exception of one hatchling that was fed nothing in this period. On +October 22 the turtles were placed in a room where the temperature was +maintained constantly at zero degrees. One of the nine turtles, an +adult female, was killed with chloroform immediately prior to its +removal to the cold room. A list of the turtles used in this +experiment is given below. + + Age Carapace Weight + class length in mm. in grams + + 1) Hatchling 33.1 8.4 + 2) Hatchling[A] 29.9 6.7 + 3) Juvenile 52.5 29.3 + 4) Juvenile 50.2 26.1 + 5) Adult [Male] 125 376 + 6) Adult [Female] 118 400 + 7) Adult [Male] 119 386 + 8) Adult [Female] 110 325 + 9) Adult [Female] 115 ---- + + [A] Starved. + + +Turtles were kept in the cold room for periods of 100 minutes +(hatchlings and juveniles) and 200 minutes (adults). The entire +experiment, including the time in which the turtles were allowed to +warm after they were taken from the cold room, covered a period of +nearly six hours (375 minutes) during which the turtles were under +constant observation. Individual body temperatures were taken +continuously in this period (39 for each juvenile and 24 for each +adult) in the order that the turtles were numbered; gaps between +records of the body temperature of a given individual therefore +represent the time required to record temperatures for the rest of the +turtles in the group. The rates of rise and fall of temperature for +each of the nine turtles considered are shown as a graph in Figure 23. +Rate of temperature change was inversely proportional to bulk; +hatchlings, for example, cooled and warmed a little more than twice as +rapidly as did adults. Rate of temperature change was intermediate in +juveniles but was more nearly like that of adults in the warming phase +and closer to that of hatchlings in the cooling phase (Table 5). + +Considering that hatchling no. 2 was smaller than no. 1, the rate of +change in its temperature did not seem to be significantly altered by +starvation. The adult males showed a tendency to change temperature +faster than adult females even though both males were larger than any +of the females. The slight difference in rate of temperature change +between the sexes (Fig. 23) may have been fortuitous. + +One hatchling (No. 1), when its temperature dropped below one degree, +fully extended all four limbs and the body was elevated and only the +anterior edge of the plastron was in contact with the confining glass +dish. Raising the body from an uncomfortably cold or hot substrate is +a well known phenomenon in many lizards and in crocodilians, but to my +knowledge has not been reported for turtles. + + + TABLE 5.--Average Rate of Change in Temperature (Expressed in Degrees + per minute) for four Groups of Turtles Subjected to Temperature + of Zero Degrees and then Allowed to Warm at 27 Degrees + (Centigrade). + ==================+========+=========+============= + | | Cooling | Warming + GROUP | Number | phase | phase + | | | (to 25A deg.) + ------------------+--------+---------+------------- + Hatchlings | 2 | .282 | .310 + | | | + Juveniles | 2 | .264 | .180 + | | | + Adult [Male] | 2 | .122 | .152 + | | | + Adult [Female] | 3 | .119 | .130[B] + | | | + Adult (all) | 5 | .120 | .138 + ------------------+--------+---------+------------- + + [B] None of the females reached a temperature of 25A deg. before + the experiment was terminated. + + + [Illustration: FIG. 23. Changes in temperature of the body of + four juvenal (nos. 1 to 4) and five adult individuals of + _T. o. ornata_ (nos. 5 to 9) exposed to a constant air + temperature of zero degrees Centigrade for periods of 100 and + 200 minutes, respectively. The vertical arrows indicate when + the turtles were removed to an air temperature of 27 degrees. + Sizes and weights of the turtles used are given in the text. + Turtle number nine, a female, was killed by means of chloroform + before experiment began. Rate of change in temperature in + specimens was inversely proportional to size. All turtles + survived the experiment.] + +Hibernating turtles and those experimentally chilled were usually +comatose but were almost never completely incapacitated even at +temperatures at or near zero degrees. Experimental pinching, probing, +and pulling revealed that muscles operating the neck, the limbs, and +the lobes of the plastron could be controlled by the turtle at low +temperatures; hissing, resulting from rapid expulsion of air through +the mouth and nostrils (when the head and limbs are drawn in +reflexively) occurred at all body temperatures but was sometimes +barely audible in the coldest turtles. Of all living turtles observed, +only two (hatchlings 1 and 2 in coldroom experiment) were completely +immobile at low temperatures, failing to respond even to pinpricks at +body temperatures of 0.8 and 1.7 degrees, respectively, although other +turtles, under the same experimental conditions, consistently gave at +least some response to the same stimulation. + +Turtles chilled experimentally continued to move about voluntarily, +albeit sluggishly, at temperatures much lower (2.5A deg. for each of four +adults; 10.0A deg. and 6.2A deg. for two juveniles) than those at which +locomotion was resumed in the warming phase (13A deg. for the adults, 21.7A deg. +and 20.1A deg. for the juveniles). Hatchlings chilled so rapidly that it +was difficult to ascertain accurately the temperature at which +inactivity was induced. Juveniles became active gradually, moving +slowly about when the body temperature reached approximately 20 +degrees but not attempting more strenuous activities such as climbing +the walls of enclosures, until body temperatures of 22 to 25 degrees +were attained. Adults, on the other hand, exhibited "normal" activity +as soon as they became voluntarily active. + +The ability of ornate box turtles to move about when the body +temperature is near the lethal minimum probably enables those caught +in the open by a sudden drop in environmental temperature to find +cover that keeps them from freezing to death. Prolonged chilling, on +the other hand, seems to create a physiologically different situation; +the temperature at which activity is resumed is higher and subject to +less variation. + +Juveniles were more rapidly affected by environmental temperatures, +were subject to different thresholds, and were inactive over a wider +range than were the adults. Indeed, the _rate_ of chilling, rather +than absolute body temperature alone, might in large measure influence +the reactions of turtles to environmental temperatures. If this be so, +smaller turtles, having a narrower thermal range of normal activity, +must lose at least some of the advantages gained by their ability to +warm up more rapidly. + +Hatchlings and juveniles at the Damm Farm were always active on days +when at least some adults were also active. Fitch (1956b:466) found +that, in northeastern Kansas, species of small reptiles and amphibians +are active earlier in the season than larger species and that the +young of certain species become active earlier than adults. Fitch +stated, "... small size confers a distinct advantage in permitting +rapid rise in body temperature by contact with warmed soil, rock or +air, until the threshold of activity is attained"; he pointed out also +that young animals, if able to emerge earlier than adults, would +benefit from a longer growing season. Hatchlings and juveniles of _T. +ornata_ would benefit greatly from an extra period of activity of say, +one or two weeks in spring and a similar period in autumn, especially +if food were plentiful. The extra growth realized from such a "bonus" +period of feeding would significantly increase the chance of the +individual turtle to survive in the following season of growth and +activity. + +Ornate box turtles are active within a narrower range of temperatures +than are aquatic turtles in nearby ponds and streams of the same +region. Observations by William R. Brecheisen and myself on winter +activity of aquatic turtles indicate that, in Anderson County, Kansas, +the commoner species (_Chelydra serpentina_, _Chrysemys picta_, and +_Pseudemys scripta_) are more or less active throughout the year; +although they usually do not eat in winter, they are able to swim +about slowly and in some instances (_P. scripta_) even to carry on +sexual activity at body temperatures only one or two degrees above +freezing. But, ornate box turtles hibernating in the ground a few +yards away are incapable of purposeful movement at such low body +temperatures. + + + + +HIBERNATION + + +In northeastern Kansas ornate box turtles are dormant from late +October to mid-April--approximately five and one half months of the +year. Individuals may be intermittently active for short periods at +the beginning and end of the season, however. Once a permanent +hibernaculum is selected dormancy continues until spring; unseasonably +warm weather between mid-November and March does not stimulate +temporary emergence. There is little movement during dormancy except +for the deepening or horizontal extension of the hibernaculum. + +Woodbury and Hardy (1948:171) found desert tortoises (_Gopherus +agassizi_) in dormancy from mid-October to mid-April in southwestern +Utah; some tortoises became temporarily active on warm days in winter. +Cahn (1937:102) was able to compare hibernation in several individuals +each of _T. ornata_ and _T. carolina_, kept under the same conditions +in Illinois. Individuals of _T. ornata_ burrowed into the ground in +October, two weeks before those of _T. carolina_ did, and continued to +burrow to a maximum depth of 22A1/2 inches. Some individuals of _T. +carolina_ spent the entire winter in the mud bottom of a puddle and +became semiactive on warm winter days. Other individuals of _T. +carolina_ burrowed nearly as deeply as did _T. ornata_. Individuals of +_T. ornata_ emerged from hibernation one or two weeks later in the +spring than did those of _T. carolina_. There are some indications +that populations of _T. carolina_ in eastern Kansas are dormant for a +shorter period of time than those of _T. ornata_ but comparative +studies are needed to verify this. Richard B. Loomis gave me a large +female of _T. carolina_ that he found active beside a highway in +Johnson County, Kansas, on November 23, 1954; on that date most +individuals of _T. ornata_ under my observation had already begun +permanent hibernation but a few at the Reservation were still +semiactive. + +Fitch (1956b:438) listed earliest and latest dates on which box +turtles were active at the Reservation in the years 1950 to 1954; in +the five year period box turtles were active an average of 162 days +per year (range, 140-187) or approximately 5.3 months of the year. It +is significant that 1954, having the most days of activity was, +according to my studies of growth-rings, an exceptionally good year +for growth. Fitch's data indicate the approximate season of growth and +reproduction but not of total activity, since he did not take into +account the sporadic movements of box turtles in late fall and early +spring. + +Activity in autumn is characterized by movement into ravines and low +areas; many turtles move into wooded strips along the edges of fields +or small streams. Sites protected from wind, providing places for +basking and for burrowing, are sought. Burrows of other animals, along +the banks of ravines, were often used for temporary shelter; +overhanging sod at the lips of ravine-banks provided cover beneath +which turtles could easily burrow. After mid-October progressively +fewer box turtles were found in open places and activity was +restricted to a few hours in the warmest part of the day. + +Low air temperature probably is the primary stimulus for hibernation. +Autumn rains are usually followed by a decrease in general activity. +Rain probably hastens burrowing by softening the ground. + +Ornate box turtles more often than not excavate their own hibernacula. +Digging begins with the excavation of a shallow form which is deepened +or extended horizontally over a period of days or weeks. Such +hibernacula are sometimes begun at the edges of rocks or logs; the +overhanging edge of an unyielding object acts as a fulcrum on the +shell and hastens digging. Ornate box turtles are slow but efficient +burrowers. + +Forms in open grassy areas are begun at an angle of 30 to 40 degrees; +an adult box turtle requires approximately one hour to burrow far +enough beneath the sod to conceal itself but can dig into soft, bare +earth much more rapidly. Once a hibernaculum is begun, all four feet +are used for its excavation, the front feet doing most of the digging +and the hind feet pushing loose earth to the rear. + +Several turtles were seen entering burrows and dens in late autumn and +trailing records showed that some individuals visited several of these +shelters in the course of a single day. + +By means of systematic probing of known hibernacula it was found that +they are deepened gradually in the course of the winter. Depth seems +to be governed by the temperature of the soil. Hibernacula in wooded +or sheltered areas were ordinarily shallower than hibernacula in open +grassland. + +In the autumn of 1953-54 two pens were constructed at the Reservation +in order to study hibernation; one pen was on a wooded hillside and +the other was on open grassland. Turtles in the grassland pen were in +newly excavated hibernacula, just beneath the sod, on October 25 and +did not emerge for the remainder of the winter, whereas turtles in the +woodland pen were intermittently active until November 10. +Correspondingly, turtles in the grassland pen descended to depths of +eight and one half and 11A1/2 inches, respectively, whereas those in +the woodland pen were covered by a scant six inches of loose earth and +leaf litter. In 1954 four turtles were traced (by means of trailing +threads) to hibernacula on wooded slopes at the Reservation; two +entered permanent hibernacula on November 13 and two remained +semiactive until sometime after November 20. All four turtles spent +the winter in hibernacula that were not more than six inches deep. +Temperatures of the soil at a depth of nine inches were usually +slightly lower at the grassland pen than at the woodland pen on a +given date. It is probably significant that individuals with trailing +devices and individuals in experimental pens furnish the latest +records for autumn activity. The unnatural conditions created by +confining the turtles in pens restricted the number of hibernation +sites that were available to them; although trailing devices did not +affect the normal movements of box turtles on the surface of the +ground these devices certainly hampered the turtles somewhat in +digging. However, it is noteworthy that box turtles are able to move +about after mid-November, whether this is of general occurrence under +more natural conditions or not. Depths of hibernacula at the Damm Farm +were also influenced by amount of vegetation or other cover. Maximum +depth of hibernacula in more or less open situations ranged from seven +to 18 inches whereas a female hibernating in a ditch that was covered +with a thick mat of dead grasses was four inches beneath the surface +of the soil, and another female was only two and one half inches below +the floor of a den. + +Several _T. ornata_ kept by William R. Brecheisen in a soil-filled +stock tank on his farm in the winter of 1955-56, burrowed to maximum +depths of seven to eight inches in the course of the winter. A layer +of straw covered the soil. All the turtles were alive the following +spring except for one juvenile, found frozen at a depth of one inch on +December 30 (the lowest air temperature up to this time was +approximately -12A deg.). Three adult and 24 juvenal _T. ornata_ +hibernating in the earth of an outdoor cage at the University of +Kansas in the winter of 1955-56, were all dead on December 3 after air +temperatures had reached a low of -12 degrees. + +Ornate box turtles are usually solitary when hibernating; in the rare +instances in which more than one turtle is found in the same +hibernaculum, the association has no social significance and is simply +a reflection of the availability and suitability of the hibernaculum. +The only communal hibernaculum--the "Tree Den"--at the Damm Farm was +discovered on October 16, 1955, after a turtle was traced to it by +means of a trailing thread. The flask-shaped cavity, approximately two +and one-half feet deep, in the north-facing bank of a narrow ravine, +had an entrance one foot wide and nine inches high, nearly flush with +the bottom of the ravine. Grasses on the bank of the ravine hung over +the entrance and nearly concealed it. The steep sides of the ravine +protected the entrance from wind. + +Seven turtles were in the den when it was discovered, and on each of +five subsequent visits from October 20, 1955, to March 6, 1956, fewer +turtles were found in the den. Figure 24 shows the approximate length +of stay of each known occupant of the den. Only one of the turtles +(an adult female) that left the den returned. Turtles found in the den +on three visits in October were more or less torpid and were seen +easily from the entrance but on November 6 the two remaining +individuals had burrowed into the sides and floor of the den. + +Three turtles (one female, one male, and one juvenile) were found in +separate form-hibernacula within a few inches of one another on +November 6, 1955 (Pl. 21, Fig. 2). The common entrance to all three +hibernacula was a shallow depression that resulted from an old +post-hole. Soil in the depression was loose and moist and ideal for +burrowing. The three hibernating turtles were situated, in a vertical +plane, at depths of 18 ([Male]), 12 (juvenile), and seven ([Female]) +inches. One of the turtles hibernating at this place on November 6 was +basking on October 30 in the shelter of some tall weeds a few feet +from the hibernaculum. + + [Illustration: FIG. 24. The approximate length of stay of each + known occupant of a den that was examined six times in the + winter of 1955-1956 at the Damm Farm. Most of the occupants + used the den as a temporary shelter and sought permanent + hibernacula elsewhere. One turtle left the den for + approximately two weeks and then returned to it for the rest + of the winter. The temperature of the air outside the den (A) + and the average body temperature of turtles in the den (B) are + given at the bottom of the diagram for each date the den was + examined. The symbol "J" represents a juvenal turtle.] + +In general, body temperatures approximated the temperature of the soil +around the turtle. Body temperatures tended to be slightly higher than +soil temperatures in November and December but were slightly lower +than soil temperatures in the months of February and March. The lowest +body temperature recorded for any turtle that survived a winter was +2.7 degrees, taken from an adult female on December 26, 1955. Body +temperatures one to three degrees higher were common in the coldest +part of the winter. Turtles in shallow hibernacula, like those +observed in wooded areas at the Reservation, are probably subjected to +freezing temperatures at least for short periods but I have no records +of body temperatures this low, except where they were induced +experimentally. Turtles exposed to temperatures of zero degrees or +slightly lower would retain enough heat to survive without freezing +for a period of several hours or even a day if well insulated. A +temperature gradient exists within the body; cloacal temperatures, for +example, differ from temperatures deep in the colon and temperatures +in the dorsal and ventral parts of the body cavity (taken by +manipulating the bulb of the thermometer while it was in the colon) +differ from one another. Probably, therefore, some parts of some +turtles--probably the top of the shell or the extremities--freeze in +winter without causing the death of the turtle. Ewing (1939:91) found +a female of _T. carolina_, just emerging from hibernation, that had +lost some scutes from its carapace; he found the missing scutes in the +hibernaculum and attributed their loss to severe temperatures in the +winter of 1933-34. + +The incidence of mortality due to freezing is unknown for most species +of reptiles. The observations of Bailey (1948) on DeKay snakes +(_Storeria dekayi_) and Legler and Fitch (1957) on collared lizards +suggest that rates of mortality are high in dormant reptiles. Bailey +(_op. cit._) suggested that winter mortality might act as a natural +check on snake populations. Neill (1948a:114) thought more box turtles +(_T. carolina_) were killed in Georgia by cold weather in late autumn +than "... by all other factors together," and that this winter +mortality acted as an effective check on population levels. Neill +reported that many turtles left their burrows in late autumn and began +to forage; if the temperature dropped suddenly, the turtles became +"... too torpid to dig" and froze. + +If ornate box turtles are occasionally caught in the open by a sudden +cooling of air temperature, it would occur at a time of year when +temperatures would approximate freezing but would drop not far below +this level; laboratory and field records show that adults could +probably survive these low temperatures overnight and warm up +sufficiently on the following day to seek adequate shelter. Box +turtles deepening their burrows in winter do so at body temperatures +somewhat lower than 10 degrees (near the minimum temperature at which +co-ordinated activity was observed in the laboratory); turtles found +in the open in late October were known to burrow into the ground at +body temperatures of approximately 15 degrees. + +Emergence from hibernation usually occurs in April but in some years a +few turtles may emerge as early as the first week of March. Emergence +is stimulated by temperature and humidity. Fitch (1956b:438) stated +that emergence was delayed until "... the ground has been sufficiently +moistened and until air temperatures have reached at least 26A deg.." Box +turtles at the Reservation emerged on April 21 in 1954 and from April +16 to 17 in 1955. William R. Brecheisen found recently emerged box +turtles in Anderson County on April 2, 1955, and March 6, 1956. + +Turtles were found facing upward in their hibernacula in early March. +As the temperature of the soil rises, they move slowly upward, usually +following the route by which they entered. They remain just below the +surface of the soil for a week or two before actually emerging; this +final phase of emergence is probably hastened by spring rains that +soften the soil. Activity may be sporadic after emergence if the +weather is cold. + +A number of box turtles at the Reservation emerged in a cold rain in +1954 when the temperatures of the air and ground were 16 and 13 +degrees, respectively, but remained inactive for several days +afterward. In 1955 the air and ground temperatures were higher (28A deg. +and 17A deg., respectively) on the day of emergence and box turtles became +active almost immediately. + + + + +DIET + + +Published information on the food of _T. ornata_ consists of a few +miscellaneous observations. Cahn (1937:103) opened five stomachs that +contained partly digested vegetable matter but no insects or other +animal food: Ortenburger and Freeman (1930:187) noted that +grasshoppers were a main part of the diet of _T. ornata_ in Oklahoma +and that turtles displayed unsuspected agility in catching them. Those +authors also saw turtles eating caterpillars and robber flies. +Strecker (1908:79) stated that "The natural diet of this species +consists of vegetable matter and earthworms." Norris and Zweifel +(1950:3) observed the feeding habits of captive _T. o. luteola_. +Coyote melon (_Cucurbita foetidissima_) was eaten with reluctance but +a collared lizard (_Crotaphytus collaris_) was quickly devoured. +Tadpoles of _Scaphiopus hammondi_ were caught in a small pool and +eaten. Adults of the same species were rejected after being caught; +box turtles were seen wiping their mouths after rejecting adult toads. +The authors suggested that _T. o. luteola_ is an important predator of +_Scaphiopus hammondi_, since the two species occur together in many +areas and the emergence of both is controlled to a large extent by +rainfall. One individual of _luteola_ was seen eating a dead box +turtle on a road. + +Captive individuals of _T. ornata_, observed in the present study, ate +nearly every kind of animal and vegetable food given to them. Table +scraps, consisting chiefly of greens, various fruits and vegetables, +meat, and cooked potatoes, formed the main diet of turtles kept in +outdoor cages. + +A number of persons have told me of ornate box turtles eating the +succulent stems and leaves, and the fruits of various garden plants; +similar incidents probably occur in areas of native vegetation. J. +Knox Jones told me he saw an individual of _T. ornata_ eating a +spiderwort (_Tradescantia_ sp.) in Cherry County, Nebraska. + +Sight-records of foods eaten by box turtles at the Damm Farm +(excluding the many records of individuals foraging in dung or eating +mulberries) were for grasshoppers, caterpillars, and various kinds of +carrion. Box turtles were often seen eating grasshoppers on roads in +early morning; Sophia Damm told me of frequently seeing individuals +catching grasshoppers in her garden. Ralph J. Donahue told me that on +his farm in Bates County, Missouri, an individual of _T. ornata_ made +a circuit of the lawn each morning in summer and ate all the cicadas +(_Magicicada septendecim_) found. + +Vertebrate remains found in the stomachs of box turtles seem to result +chiefly from the ingestion of carrion. One box turtle ate a white egg +(unidentified) that had fallen from a nest and another was seen with a +blue down feather clinging to its mouth. Several colleagues have told +me of box turtles eating small mammals caught in snap-traps and Marr +(1944:489) reported a similar incident. J. Knox Jones told me he once +found an ornate box turtle in the nest of a blue-winged teal in Cherry +County, Nebraska; the three eggs in the nest had been broken. The only +authentic record of an ornate box turtle preying on a vertebrate under +natural conditions was one supplied by Ralph J. Donahue who saw an +adult catch and eat one of a brood of bobwhite quail. In many areas +where box turtles are abundant, it is the opinion of local residents +that the turtles decimate populations of upland game birds by eating +the eggs and young of these birds; these opinions result probably from +rare encounters such as the one described by Donahue. I believe that +box turtles at the Damm Farm were sometimes able to catch young frogs +and tadpoles (chiefly _Rana catesbeiana_ and _R. pipiens_) at the +margins of ponds. In autumn literally thousands of young _Rana_ were +present in these places. + +Ornate box turtles ordinarily attempt to catch and, without further +examination, to eat, small objects moving on the ground, but are more +critical of stationary objects. Captive turtles, for example, would +immediately chase and seize a grape that was pulled or rolled slowly +across a floor but a stationary grape was examined and then smelled +before it was eaten. Similar observations were made a number of times +with living and dead insects in the field and in the laboratory. A +turtle discovering an object that is of possible value as food, +approaches it closely, turns the head from side to side (presumably +using the eyes alternately to examine the object), and then, with head +cocked at a slight angle, momentarily presses the nostrils against the +object (Pl. 28, Fig. 4). If acceptable as food, the object is then +swallowed whole or taken into the mouth with a series of bites; large +insects are usually broken into several pieces in the process of being +bitten and swallowed. Larger objects, such as dead vertebrates, are +torn to pieces with the beak and forefeet before they are swallowed. +Hatchlings, when fed for the first time, ignored inanimate foods but +eagerly chased mealworms, catching them usually by the anterior end. +The tendency of the young of certain species of turtles (especially +captives) to be more carnivorous than adults is probably due to the +association of movement with food; recognition of inanimate objects as +food is presumably learned by older individuals. + +Mulberries (_Morus rubra_), when they are abundant, constitute all or +an important part of the diet of ornate box turtles. On June 4, 1955, +William R. Brecheisen and I drove along a road in Anderson County, +Kansas, and stopped at each mulberry tree that we saw beside the road; +we found at least one specimen of _T. ornata_ under nearly every tree. +Approximately twenty box turtles were collected in this manner in a +little more than one hour. The heads and necks of most were stained +dark-red from the fruit and, in some, nearly the entire shell was +stained. Dissection of these turtles revealed that their stomachs were +distended to two or three times normal size with mulberries; no other +kinds of food were found in the stomachs. Some of the turtles voided +purplish-black fluid from the cloaca when we handled them; the color +of the fluid presumably resulted from mulberries. + +Several turtles were observed through binoculars as they foraged. +Individuals snapped or lunged periodically at objects on the ground +along the route of travel. Upon reaching an area where cow dung was +abundant, a turtle would move directly to a pile of dung and begin +tearing it apart with the forelegs or burrowing into it. Turtles most +often foraged in cow dung that had a superficial, dried crust. The +invertebrate fauna of older dung was probably greater than that of +fresh dung. Adult and larval insects were eaten, along with quantities +of dung, as they were uncovered. Sometimes box turtles chased and +caught larger insects that ran a foot or more away from the pile of +dung; the turtles could cover the distance of one foot with three or +four quick steps. Depressions made by box turtles in cow dung, as well +as drier cow dung that had been more completely dissected, were +regarded as characteristic "sign" of _T. ornata_ at the Damm Farm and +in other areas studied (Pl. 26). Several persons have told me of box +turtles "eating cow dung"; these reports, most of them made by +competent observers, probably result from observations of box turtles +ingesting cow dung incidentally, along with some unseen item of food. + +Contents of stomachs were analyzed. Scats and contents of lower +digestive tracts, although obtained in large quantity, were unsuitable +for analysis because of the fragmentary nature of the foods they +contained. Relative amounts of various kinds of foods in stomachs were +estimated; volume was determined by displacement of water or fine +shot. + +Twenty-three stomachs of adults were selected at random (except for +the fact that empty stomachs were discarded) from more than a hundred +specimens collected in Douglas County, Kansas, in the period from +June, 1954, to June, 1957; the sample included stomachs obtained in +nearly all the months of the season of activity. Kinds of foods in +stomachs did not differ significantly in regard to the sex of the +turtles or to time of year. The stomach of each of two juveniles +(included in Table 6) contained a greater variety of animal food than +did the stomach of any adult, but no kind of animal was eaten by the +juveniles exclusively. + +Each of the 23 stomachs contained animal matter and, in addition, all +but two contained at least some plant material from dung, which +constituted up to 20 per cent of total stomach contents. + +Insects were present in each of the 23 stomachs and constituted the +bulk of the animal matter; beetles, caterpillars, and grasshoppers +(ranked in descending order) were the kinds occurring most frequently +and constituting the largest average percentages of total +stomach-contents. Most of the beetles were scarabaeids and carabids; +the bulk of the caterpillars were noctuids and arctiids. Grasshoppers, +with one exception, were of a single species, _Melanoplus +differentialis_. It is noteworthy that two of the kinds of insects +frequently eaten (differential grasshoppers and noctuid caterpillars) +are of economic importance in that they damage crops. + + + TABLE 6.--Kinds of Animals Found in the Stomachs of 25 _Terrapene o. + ornata_ of Both Sexes (23 adults, 2 juveniles) from Douglas + County, Kansas. Frequency of Occurrence (number of stomachs in + which found) is Given for Each Item Listed. + =======================================+============================= + | FREQUENCY OF OCCURRENCE + |--------+-----------+-------- + | Adults | Larvae | Total + ---------------------------------------+--------+-----------+-------- + Gastropoda | | | + _Helisoma_ sp | 1 | | 1 + _Succinia_ sp | 1 | | 1 + _Polygyra_ sp | 1 | | 1 + _Retinella_ sp | 1 | | 1 + ---------------------------------------+--------+-----------+-------- + Crustacea | | | + _Procambaris gracilis_ | 1 | | 1 + _Armadillidium vulgare_ | 4 | | 4 + ---------------------------------------+--------+-----------+-------- + Orthoptera (Locustidae) | | | + Locustinae (_Melanoplus | | | + differentialis_) | 13 | | 13 + Oedipodinae | 1 | | 1 + | | | + Lepidoptera (unspecified) | | 1 | 1 + Arctiidae | | 9 | 9 + Noctuidae | | 10 | 10 + Pyralidae | | 1 | 1 + Sphingidae | | 1 | 1 + | | | + Diptera (Sarcophagidae) | | 1 | 1 + | | | + Coleoptera (unspecified) | 3 | | 3 + Cantharidae | | 1 | 1 + Carabidae (unspecified) | 6 | | 6 + (_Eumolops colossus_) | 1 | | 1 + Cerambycidae (_Prionus fissicornis_) | 1 | | 1 + Chrysomelidae | | | + (_Diabotrica 12-punctata_) | 1 | | 1 + Curculionidae (_Calendra parvulus_) | 3 | | 3 + Lampyridae (_Photinus pyralis_) | 2 | | 2 + (_Photuris sp._) | | 1 | 1 + Phengodidae | | 1 | 1 + Scarabaeidae | 11 | | 11 + | | | + Hymenoptera (Formicidae) | 2 | | 2 + ---------------------------------------+--------+-----------+--------- + Phalangida | 1 | | 1 + | | | + Araneida (_Epeira_) | 1 | | 1 + | | | + Diplopoda | 1 | | 1 + ---------------------------------------+--------+-----------+--------- + Vertebrata (carrion) | | | 4 + ---------------------------------------+--------+-----------+--------- + + +TABLE 7.--Occurrence of Insects, by Frequency and Volume, in Stomachs + of 23 _Terrapene ornata_ from Douglas County, Kansas. Relative + Volume is Based on Total Amount of Food Material Present, Excluding + Stones and Vegetable Material Contained in Dung. + ===================+=========+=============+==============+========== + | Insects | Orthoptera | Lepidoptera |Coleoptera + | (all) | | (larvae) | + -------------------+---------+-------------+--------------+---------- + Average | | | | + volumetric | | | | + percentage | 88.6 | 28.7 | 26.9 | 32.5 + -------------------+---------+-------------+--------------+---------- + Range | | | | + (volumetric | trace | | | + percentage) | to 100 | 0 to 100 | 0 to 100 | 0 to 100 + -------------------+---------+-------------+--------------+---------- + Frequency of | | | | + occurrence | | | | + (percentage | 100 | 52 | 65 | 74 + of total stomachs | | | | + in which found) | | | | + -------------------+---------+-------------+--------------+---------- + + +Snails, sowbugs, and the one individual of crayfish found in stomachs +were kinds that could be expected to occur in moist grassland or in +wooded stream courses. Mulberries were present in one stomach and +fragments of bird's-nest fungi (_Cyathus striatus_) were present in +another. Carrion consisted of remains of mammals and birds; the only +identifiable items were bones of the eastern cottontail (_Sylvilagus +floridanus_) and a chicken. Stones up to seven millimeters in diameter +were found in many stomachs; stones constituted as much as half of +total stomach-contents. Presumably the stones were accidentally +swallowed when food was taken from the ground. + +The few adequate reports on dietary habits of _T. carolina_ (Allard, +1935:325-326; Carr, 1952:147, 150, 152, 153; Stickel, 1950:361; +Surface, 1908:175-177) indicate that the species is omnivorous but +that individuals tend to be herbivorous or carnivorous at certain +times. Ornate box turtles resemble _T. carolina_ in being +opportunistic feeders but rely on insects as a staple part of the +diet. In this respect the ornate box turtle seems to differ from all +other kinds of box turtles in the United States and it is probably +unique in its habitual utilization of dung communities as a source of +food. + + + + +POPULATIONS + + +Ornate box turtles were probably more numerous on the Damm Farm than +any other kinds of reptiles, excepting skinks (_Eumeces fasciatus_ and +_E. obsoletus_), and were by far the most conspicuous element of the +reptilian fauna. + +The 194 box turtles that were marked at the Damm Farm were captured a +total of 437 times. Seventy-nine (41 per cent) individuals were +recaptured at least once, 49 (25 per cent) twice, 29 (15 per cent) +three times, and 20 (10 per cent) were recaptured at least four times. +Only three individuals were recaptured more than eight times. The +greatest number of recaptures for a single individual, an old female, +was 23. + +In all, 185 turtles (95 per cent of total recorded at Damm Farm) were +captured on the pasture. Of these, 73 were in the northwest corner +area, 44 in the house pond area, and 35 in the southern ravine area. +The density of the population at the Damm Farm, considering the entire +area, was .88 turtles per acre; for the woodland area alone, density +was .41 turtles per acre and for the pasture alone, density was 1.49. +Acreage and population density in the northwest corner, house pond, +and southern ravine areas were respectively, 28 acres with 2.6 turtles +per acre, 7 acres with 6.3 turtles per acre, and, 17 acres with 2.6 +turtles per acre. The densities noted above for the wooded area and +for the entire Damm Farm are low as a result of incomplete sampling in +the wooded area. Estimates of population density for the subdivisions +of the pasture seem more closely to approach the true population +density in areas of favorable habitat. + +Fewer unmarked turtles were captured as the study progressed, but they +were still being captured occasionally when field work was terminated. +In order to estimate the number of turtles in the population at the +Damm Farm the "Lincoln Index" (Lincoln, 1930) was used to compare the +ratio of marked individuals to total number of individuals (17:56) in +collections for June, 1956, to the ratio of marked individuals as of +July 31, 1955 (87) to total individuals in the population; the result +was 286. + +Fitch (1958:78) estimated the population of _T. ornata_ in one area of +the Reservation (including woodland and ungrazed pasture) to be .076 +turtles per acre. Stickel (1950:373) estimated the population of adult +_T. carolina_ to be four to five turtles per acre in favorable habitat +at the Patuxent Research Refuge, Laurel, Maryland; juveniles comprised +less than ten per cent of the population. + +Of the 194 turtles marked at the Damm Farm, 103 (53 per cent) were +adult or subadult females, 61 (31 per cent) were mature males, and 30 +(16 per cent) were juveniles of undetermined sex. The ratio of males +to females was then, 1.00 to 1.69, and the ratio of juveniles to +adults was, 1.00 to 6.47. Eighteen of the 194 individuals were +juveniles less than 90 millimeters in plastral length and only six had +plastra less than 60 millimeters long (Fig. 25). The unbalanced ratio +between males and females may result, in part, from sexual differences +in habits. The studies of Carr (1952:9), Fitch (1954:140), Forbes +(1940:132), Legler (1954:138), and Risley (1933:690), have shown, +however, that unbalanced sex ratios, with females outnumbering males, +are found in several species of reptiles, especially in turtles. + +Records for 540 adult _T. ornata_ collected at the Damm Farm, the +Reservation, and on roads in eastern Kansas, show that females +outnumber males just before and during the nesting season and again in +late autumn (Fig. 26). The high incidence of females in May, June, and +July, can be explained by their more extensive movements associated +with nesting in these months. I have no explanation for the increased +number of females captured in late autumn. In April and August, the +only two months in which males were more abundant than females, the +samples were small. The number of juveniles collected was too small to +allow any trustworthy conclusions concerning their seasonal incidence; +a few juveniles were taken in nearly all the periods in which adults +were active. + +Risley (1933:690), studying _Sternotherus odoratus_ in Michigan, found +an over-all sex ratio of 1.0 male to 2.3 females; the percentage of +females in collections ranged from 50 to 71 per cent in April and most +of May and rose to 83 and 85 per cent in late May and mid-June, +respectively. + +The infrequency with which hatchlings and small juveniles of ornate +box turtles are observed is well known to naturalists. Several of my +colleagues who are expert field observers and who have lived in areas +where ornate box turtles are abundant, have never seen hatchlings; +many other persons have seen only one or two. Rodeck (1949:33), noting +the abundance of coleopterous insects in the scats of captives and the +rarity of individuals of all age groups during dry periods in +Colorado, commented, "It is possible that the young are even more +subterranean than the adults. Perhaps they spend their early years in +rodent or other burrows where there is a fairly abundant insect fauna. +Increasing size might force them to the surface for feeding, with a +daily return to a burrow for resting and protection." + + [Illustration: FIG. 25. Composition of the population of + _T. o. ornata_ at the Damm Farm based on the 194 individuals + marked there in the years 1954 to 1956. Individuals smaller + than 100 mm. ordinarily could not be sexed accurately and are + shown as open bars. Open bars in the groups larger than 100 mm. + are for females, whereas solid bars are for males.] + +My own experience in the field has shown that small examples of _T. +ornata_ are not so rare as previous workers have believed. Small box +turtles occupy the same microhabitat as do the adults and seem not to +be more aquatic or subterranean in habits. Juveniles are found in +burrows, in marshy areas, and in other sheltered places, but so are +adults. Most of the juveniles that I found were in open situations +where adults were abundant, sometimes within several inches of a place +where an adult was feeding or basking. Nearly every one of the smaller +turtles was discovered when I was closely scrutinizing some other +object on the ground; sometimes juveniles were actually touched before +being seen. Most juveniles were covered with cow dung or mud and +blended so well with the substrate that they were detected only when +they moved. It is likely that only a small number of the young box +turtles present in an area is ever actually observed. Young are more +vulnerable to predation and injury because of their small size, soft +shells, and immovable plastra. They evidently rely, to a large extent, +on inconspicuousness for protection. + + + [Illustration: FIG. 26. The seasonal abundance of females of + _T. o. ornata_ based on 540 adults captured at the Damm Farm, + the Reservation, and on roads in eastern Kansas, in the years + 1954 to 1956. Records are grouped in periods of 30 days, the + periods beginning with the dates shown at the bottoms of the + bars. Juveniles are not considered. Numbers at the top of each + bar indicate the size of the sample (both sexes) and give an + approximate indication of relative seasonal abundance of + adults, except for August, when little field work was done.] + + + + +MOVEMENTS + + +The only previous study of movements of _T. ornata_ is that of Fitch +(1958:99-101). He recovered 14 marked _T. ornata_ at the Reservation a +total of 30 times, the period between recaptures varying from one to +seven years. He reported that the average radius of home range was 274 +feet (for an area of approximately 5.4 acres), excluding a single +(presumably gravid) female that moved 1830 feet in 53 days. + +Although published information on _T. ornata_ is scant, a considerable +amount of information is available concerning its congener, _T. +carolina_. The classic studies of Stickel (1950) on it constitute the +most complete account of populations and movements for any reptile or +amphibian, and probably, for any vertebrate. She found the average +home range of adults to be 350 feet in diameter. Home ranges were not +defended as territories and nearly all individuals were socially +tolerant of one another. Movements (studied by means of a +thread-trailing device) were characterized by frequent travel over the +same routes within the home range. Some turtles concentrated their +activities in only one part of the home range, moving subsequently to +another part, and some turtles had two ranges between which they +traveled at varying intervals. Females ordinarily left their home +ranges to nest. + +Other noteworthy, but less detailed, studies of populations of _T. +Carolina_ are those of Breder (1927) who found evidence of home range +and homing behavior, and of Nichols (1939b) who, after observing a +marked population on Long Island over a period of twenty years, found +evidence of homing behavior and estimated normal home range to be +approximately 250 yards in diameter. Numerous shorter papers such as +those of Schneck (1886) and Medsger (1919) document the tendency of +_T. carolina_ to remain in restricted areas over long periods. + +Important studies that indicate the presence of home range and homing +behavior in other chelonians are those of Cagle (1944) on _Pseudemys +scripta_ and _Chrysemys picta_, and of Woodbury and Hardy (1948) on +_Gopherus agassizi_. Grant (1936) and Bogert (1937) have also +indicated that movements of individuals of _Gopherus agassizi_ are +restricted to limited areas. + + +Locomotion + +Ornate box turtles moving forward over even terrain hold the plastron +a quarter to a half inch above the ground and keep the head and neck +lowered and extended. Each foreleg is brought forward and the humerus +points nearly straight ahead when the foot touches the ground. Nearly +all of the palmar surface is initially in contact with the ground but +as the body is brought forward and the humerus swings outward, only +the claws, and finally, only the two inner claws are in contact with +the ground. Of the hind feet, the medial surfaces are the principal +parts that touch the ground but some traction is derived from the hind +claws at the beginning of each cycle of the hind leg. Under normal +conditions, box turtles move slowly and pause to rest and examine +their surroundings every few feet. When resting, the plastron is in +contact with the ground, the legs relaxed, and the head and neck are +extended upward. Some turtles seeking shelter from the heat of +sunshine walk rapidly for a hundred feet or more without pausing. + +Turtles seen feeding under natural conditions displayed remarkable +agility in making lunges, consisting of one or two short steps and a +thrust of the head, at moving objects. Turtles kept in my home were +able, after being conditioned to hand-feeding, quickly to intercept a +grape rolled slowly across a linoleum-covered floor. + +Frederick R. Gehlbach told me that, of several species of captive +turtles observed by him, _T. ornata_ characteristically walked with +the plastron held well above the substrate, as did _Gopherus +berlandieri_, but that _T. carolina_ (specimens from the northeastern +U. S.) dragged their shells as they walked. Apparently _T. carolina_ +in Kansas (currently referred to the subspecies _triunguis_) differs +somewhat in gait from populations in the eastern part of the range; +several individuals of _T. carolina_ from Kansas that I observed in +captivity, kept their plastra raised well above the smooth, hard +substrate over which they walked. + +Box turtles at the Damm Farm were able easily to climb ravine banks +that sloped at an angle of 45 degrees and, with some difficulty, could +climb banks as steep as 65 degrees. Most individuals, however, were +reluctant to walk directly downward on banks as steep as 45 degrees. +Several individuals were seen to lose footing when climbing up or down +a steep bank and to roll or slide to the bottom. Ordinarily, _T. +ornata_ is able to climb over a sheer surface as high as its shell is +long, provided the surface is rough enough to give some traction to +the foreclaws. The claws of first one, then the other forefoot are +placed over the top of the barrier and then a hind foot, extended as +far forward as possible, secures a hold as the turtle goes over the +barrier. + +A number of observations on speed were made in the field where +distance traveled and time elapsed were known approximately. Speeds +ranged from 20 to 100 feet per hour in the course of foraging. Higher +speeds (400 or more feet in one hour) were for turtles moving along +pathways or seeking shelter. Gould (1957:346) observed somewhat faster +speeds in _T. carolina_ (192 feet per hour in cloudy weather and 348 +feet per hour in sunny weather); he observed individuals that had been +removed from their normal home ranges. + +Individuals of _T. ornata_ that were placed in water swam moderately +well but were clumsy in comparison to individuals of more aquatic +emyids such as _Pseudemys_ and _Chrysemys_. Box turtles were never +observed to swim voluntarily, although they were frequently found in +shallow water. On several occasions I confronted individuals at the +edge of a pond so that the only unblocked route for their escape was +through deeper water; nearly always these individuals attempted to +crawl past me, to crawl away in shallow water parallel to the shore, +or to hide in soft mud at the edge of the water. Box turtles floated +high in the water with the dorsal side upward and had little +difficulty in righting themselves when turned over. The head and neck +are extended and submerged when the turtle is swimming; forward +progress is interrupted every few moments to elevate the head, +presumably for purposes of breathing and orientation. The shell is +never submerged. The swimming of _T. ornata_ is in general like that +of _Pseudemys_ or _Chrysemys_ that have become dehydrated after long +periods out of water and cannot submerge. These more aquatic turtles, +however, quickly overcome their bouyancy, whereas examples of _T. +ornata_, even if left in water for several days, are unable to +submerge. Clarke (1950) saw an ornate box turtle swim a 60-foot-wide +stream in Osage County, Kansas; his description of swimming agrees +with that given above. + +The meager swimming ability of _T. ornata_ is of apparent survival +value under unusual conditions and enables _T. ornata_ to traverse +bodies of water that would act as geographic barriers to completely +terrestrial reptiles; however, swimming is a mode of locomotion seldom +used under ordinary circumstances. + +Gehlbach (1956:366) and Norris and Zweifel (1950:2) observed +individuals of _T. o. luteola_ swimming in temporary rain pools and +small ponds in New Mexico; the two authors last named saw an +individual quickly enter a pond and dive beneath the water after being +startled on the bank. Several of my colleagues, in conversation, have +also reported seeing _T. o. luteola_ in small bodies of water in the +southwestern United States. + + +Daily Cycle of Activity + +The daily cycle of _T. ornata_ consists basically of periods of +basking, foraging, and rest that vary in length depending upon +environmental conditions. Turtles emerge from burrows, forms, and +other places of concealment soon after dawn and ordinarily bask for at +least a few minutes before beginning to forage; foraging is combined +sometimes with basking, especially in open areas that are suitable for +both kinds of activity. Foraging usually continues until shelter is +sought sometime between mid-morning and noon. Turtles remain under +cover (or continue to forage in shaded areas) until mid-afternoon or +late afternoon when they again become active. They forage in both +morning and afternoon. Study of travel records of a few of the turtles +equipped with trailers suggests that, under normal conditions, +activity is slightly greater in forenoon than in afternoon, but that +the converse is true of gravid females seeking nesting sites. Strecker +(1908:79) reported that captive _T. ornata_, after developing a +feeding reflex, ate and retired until feeding time next day. + +As environmental temperatures rise in summer, the period of mid-day +quiescence is lengthened. In the hottest part of the year, some +turtles remain under cover for several days at a time. In periods of +clear, cool weather at the beginning and end of the growing season, +some turtles remain abroad and bask for most of the day. + +Examination of thread trails showed that activity of all individuals +except nesting females was terminated at dusk. Breder (1927:236), +Allard (1935:336), and Stickel (1950:358) reported a corresponding +lack of nocturnal activity in _T. carolina_. _Terrapene o. ornata_ in +Kansas, and _T. o. luteola_ in New Mexico (Norris and Zweifel, +1950:2)--unlike desert tortoises, _Gopherus agassizi_, which are +active at night in hot weather (Woodbury and Hardy, 1948:186)--do not +utilize the hours of darkness for foraging, even in the hottest part +of the year. + + +Seasonal Cycle of Activity + +Data obtained by mapping the movements of turtles that were equipped +with trailing devices made it possible to compare distances traveled +in the course of daily activities at different times of the year. Some +of these data are expressed graphically in Figure 27. It should be +noted that movement at all times in the season of activity was uneven; +that is to say, an individual would move several hundred feet each day +for a period of several days, and then, for an interval of one to +several days, move only a few feet from one shelter to another, or not +move at all. Such periods of rest could not be correlated definitely +with environmental conditions; some individuals were inactive on days +that were probably ideal (in terms of moderately warm temperatures and +high humidity) for activity of box turtles. Analagous rest periods +were noted in _T. carolina_ by Stickel (1950:358). + +Two males of _T. ornata_ that had been removed by me from their normal +home ranges traveled the longest average distance per day (429 feet). +Gravid females in June traveled the next longest average distance per +day (363 feet). The average distances traveled per day by non-gravid +females in June (226 feet) and July (260 feet) and by males (within +their known home ranges) in June (289 feet) were thought to +approximate normal amount of movement under average environmental +conditions. Average distance traveled per day by females in October +(152 feet) was shortest because of frequent and extended rest periods. +Nevertheless, in October actual distances traveled on days of activity +tended to be longer than in any other month. A gravid female traveled +farther in a single day than any other individual of _T. ornata_ +observed; she moved along a rock fence for approximately 700 feet, +then left the study area and moved, in a nearly straight line, 1,200 +feet across a cultivated field. Then the thread on her trailer was +expended. The total distance moved, therefore, was at least 1,900 feet +and probably more. + + [Illustration: FIG. 27. Average distances traveled per day by + males and females at different times of the year, determined by + mapping of thread trails at the Damm Farm. The diagram for + "homing males" represents the distances traveled by two males + removed from their normal home ranges to test homing ability. + The data presented are for an aggregate of 136 days of + trailing. Vertical and horizontal lines represent, + respectively, the range and mean. Open and solid rectangles + represent one standard deviation and two standard errors of the + mean, respectively.] + +An adult male at the Reservation traveled 2,240 feet in the 36-day +period from October 16 to November 20, 1954, mostly on a wooded +hillside. Eleven forms found along the route of the turtle's travels +indicated that movement took place on roughly one out of three days in +the elapsed period and demonstrated the sporadic nature of movements +in autumn. The turtle remained active for an undetermined time after +November 20. + + +Home Range + +Data obtained from trailing and various methods of recapture at the +Damm Farm indicated that each individual used only a small part of the +total study area in the course of daily activities and tended to +remain within a restricted area for a long time. + +The number of recaptures of no individual was great enough to permit +application of refined calculations of size of home range as described +by Odum and Kuenzler (1955). For individuals that were recaptured six +or more times, or individuals for which adequate trailing records were +available, the area enclosed by a line joining the peripheral points +of capture was considered adequately representative of the home range +of that individual, unless recaptures were all within a few feet of +each other or lay in an approximately straight line. If less than six +records of recapture were available, home range was estimated, in the +manner described by Fitch (1958:73), by averaging the distance between +successive points of recapture and letting this average represent the +radius of home range; the actual area of home range was determined by +the formula, [pi](R)A squared, for the area of a circle. + +Size of home ranges of males and females did not differ significantly +and data for the two sexes were combined in the final analysis. The +average radius of the home ranges of 44 adults (captured a total of +146 times) was 278 feet (extremes, 71 to 913) when computed by +measuring the distance between successive captures; the average area +of these home ranges was 5.6 acres. Data from 10 turtles that had been +recaptured only once were combined with data from 34 turtles that had +been recaptured more than once when it was found that the average size +of home range in these two groups did not differ significantly. Data +concerning the home ranges of eight of the 44 individuals were +sufficient to permit actual measurement of home ranges with a +planimeter; home ranges of these eight individuals had an average area +of five acres (extremes, 1.2 to 10.2). + +A minimum home range could theoretically consist of the smallest area +in which adequate food and shelter were available. Under favorable +conditions a turtle could stay in an area ten to twenty feet in +diameter. Although several such favorable small areas existed on the +Damm Farm, box turtles seldom stayed in one for more than a day or +two. Seemingly, therefore, factors additional to food and shelter +influence size of home range. At the Damm Farm these additional +factors seemed to be: rock fences that acted as physical barriers; +areas that were cultivated, barren, or otherwise unfavorable, acting +as ecological barriers; and, cowpaths and ravines that offered +relatively unobstructed routes along which box turtles tended to move. + +One subdivision of the main pasture, the northwest corner area, is an +example of a relatively small natural area in which many individual +box turtles had home ranges. This tract of 28 acres was roughly +triangular and was bordered on two sides by rock fences that contained +no gates or other passageways. On its third (southeastern) side the +area sloped into a deep ravine. Habitat in this subdivision of the +pasture (as well as in the other two subdivisions) was especially +favorable for box turtles because of permanent water, rocky slopes, +ravines, and several fruit trees. Box turtles usually foraged near the +rock fences and the ravine (where dung was more abundant than in other +parts of the area), and tended, as they foraged, to move parallel to +these barriers. Turtles crossing the area eventually came either to +one of the fences or the ravine. Therefore, most of the turtles in the +northwest corner area eventually completed a circuit of the area. +Turtles that came to the ravine tended to move along its bottom or +sides. Several turtles were known to cross the ravine and to forage in +the grassy area on its southeastern side. These turtles usually +re-entered the ravine by way of smaller side-ravines. Of 22 box +turtles known to have home ranges in the northwest corner area, only +two individuals (both gravid females) were known to leave the area in +the period in which observations were made. + +Two other subdivisions of the main pasture--the house pond area and +the southern ravine area--although not so distinct as the northwest +corner area in terms of limiting barriers, nevertheless constituted +separate areas of favorable habitat, each of which contained a number +of individual home ranges. Although the two areas were not far apart, +but little movement was observed of turtles from one area to the +other. The home range of only one turtle, an adult female, was known +to include parts of both areas. + +Unbroken expanses of tall grass seem not to be optimum habitat. The +crest of the hill at the Damm Farm (Pl. 17, Fig. 1) was an area of +more or less homogeneous grassy habitat. Turtles were seldom found on +the crest of the hill although this area was as thoroughly searched +for turtles as any other area. Known home ranges of nearly every +individual observed were on either one of the sides of the hill but +not on both sides. + +At several places on the border of the pasture, turtles were able to +move freely into cultivated areas but seldom did so except for +nesting. Trailing records show that most of the turtles that entered +one of the cultivated areas returned again to the pasture. + +Ornate box turtles seem to find places of shelter by trial and error +along regularly used routes of travel in their home ranges. The +individuals that I studied never returned to the same forms, and +seldom returned to the same natural burrows and dens. Probably +foraging, basking, and watering sites are found also by trial and +error. + +Stickel (1950:375) placed considerable importance on the occurrence of +transient turtles in populations of _T. carolina_; in estimating +population density, she added to her study area a peripheral strip, +half as wide as the average, estimated home range, to account for +turtles that had home ranges only partly within the study area. The +study area used by Stickel had no natural boundaries, as habitat +conditions on all sides were essentially the same as those of the +study area itself. The pasture at the Damm Farm, on the contrary, is a +relatively isolated area of natural grassland, bordered by rock +fences and cultivated fields. I believe that most of the box turtles +found on the pasture were permanent residents there. Individual box +turtles at the Damm Farm seemingly occupied but one home range and it +did not change from year to year. Populations of _T. ornata_ in areas +less isolated than the Damm Farm, like the populations of _T. +carolina_ studied by Stickel (_loc. cit._), could be expected to have +a higher percentage of transient individuals and individuals with +multiple or changing home ranges. Henry S. Fitch told me that he +considered most of the individuals of _T. ornata_ that were captured +only once at the Reservation were transients. + +Several females at the Damm Farm traveled long distances from their +home ranges to nest but other females nested within their known or +estimated home ranges. Seemingly a complex of environmental factors, +including soil texture, weather, availability of water, and possibly +the urge for random wandering in the breeding season, governs the +distances traveled by gravid females and the ultimate selection of a +satisfactory nesting site. Females, because of their more extensive +travels in the nesting season, seem more likely than males to have +multiple or changing home ranges. Males of _T. ornata_ did not +noticeably alter the extent or pattern of their movements in the +breeding season. Hibernacula, unlike nesting sites, were within the +known or estimated home ranges of all individuals studied. + + [Illustration: FIG. 28. The movements of an adult (non-gravid) + female of _T. o. ornata_ in the house pond area at the Damm + Farm during a period of 24 days in July, 1955 (solid line), and + a period of three days (broken line) in July, 1956. Solid dots + represent the points where the turtle was found as her thread + trail was mapped; hollow symbols represent points of recapture + when no trailing thread was attached to the turtle.] + +The actual home range of almost every individual studied, even +of those individuals for which the most data were available, probably +differed at least slightly from the observed or estimated home +range. One adult female, for example, was captured six times in +two years within a radius of approximately 50 feet. Another female +was found 2780 feet from her last point of capture. These last +two records were regarded as unusual; when they were grouped +with records of the 44 individuals mentioned above, the average +radius of home range for the entire group was much larger (327 +feet). + + [Illustration: FIG. 29. The movements of a gravid female of + _T. o. ornata_ in the southern ravine area at the Damm Farm in + a period of ten days in June, 1956. Her movements were, for the + most part, in and around several ravines (shown on map by + broken lines) where she was searching for a nesting site. For + explanation of symbols see legend for Fig. 28.] + + +Homing Behavior + +Gould (1957) reported that 22 of 43 _T. carolina_ moved in a homeward +direction when they were released in open fields up to 5.8 miles from +their original points of capture. Turtles oriented themselves by the +sun; homeward headings were inaccurate or lacking on overcast days +and, light reflected from a mirror caused turtles to alter their +courses. Seven of ten turtles released more than 150 miles from home +headed in directions that corresponded most nearly to the headings +last taken (at release-points near home base) and did not necessarily +correspond to the direction of home. Gould's studies point out that +box turtles perhaps practice a kind of "solar navigation." His work +raises the question of whether the movements of box turtles are guided +by the sighting of local landmarks or whether such landmarks alter the +course of movement only when acting as barriers. + +In the present study two experiments were made to determine the homing +ability of _T. ornata_. An adult male, taken from his normal home +range in the house pond area and released 1200 feet away in the +southern ravine area, traveled a generally northward course (not +northeastward in the direction of home) for five days, moving a +distance of approximately 1900 feet. His detached trailer was +recovered several days later 740 feet southeast of the last known +point in his travels (a distance that could have been covered in two +days) and 150 feet from the point of original capture; he had returned +to his home range by a circuitous route in a period of approximately +seven days. Another adult male, captured in the southern ravine area, +and released in the house pond area 1900 feet away, traveled on a +course that bore approximately 25 degrees north of true homeward +direction; after five days he was approximately 600 feet north of the +original capture point. He then began a northeastward course that took +him back to the house pond area where he remained for several days; no +further data are available for this individual. It is significant that +the homing males discussed above traveled greater average distances +per day (based on records for nine days of trailing) than any of the +other turtles studied (Fig. 27). Fitch (1958:101) released an +individual one half mile from where he captured it and, one year +later, recovered the turtle near the point of release. + + +Social Relationships + +Ornate box turtles are solitary except during periods of mating. +Meetings with other individuals in the course of foraging, basking, or +seeking shelter, are fortuitous and have no social significance. A +broad overlapping of home ranges of both sexes at the Damm Farm +suggests that box turtles do not intimidate other individuals in the +home range or exclude them from it. No instances of fighting were +observed. + +Allard (1935:336), Perm and Pottharst (1940:26), and Latham (1917) +recorded instances of fights between individuals of _T. carolina_; in +the latter two instances fights were between males. Stickel (1950:362) +observed an incident between two males that may have been a fight; +however, she was of the opinion that fights rarely occur in nature and +that box turtles do not defend territories. Evans (1954:23-25) +considered the behavior of _T. carolina_ reported by Perm and +Pottharst (_loc. cit._) to represent "territoriality." He found "... a +true hierarchy...." existing between four captive males of _T. +carolina_ and another between three captive females of the same +species; young individuals in the group raised their social level in +the hierarchy after receiving experimental doses of male hormone. +Evans (_op. cit._:25) pointed out that true tortoises (family +Testudinidae) have a more complex pattern of social behavior than do +emyid turtles. + +Observations made with binoculars from the vantage point of a blind +provide the only information that I have concerning the reactions of +box turtles to one another under natural conditions. Turtles foraging +in a bare area were not startled by the approach of other turtles, and +turtles moving across the area seemed to take no notice of turtles +already there, regardless of whether these turtles were moving or not. +Adults and subadults behaved in approximately the same manner. + +Individuals traveling or foraging in rough terrain or in grassy areas +probably are unable to see each other even when they are close to one +another. Conversely, box turtles can see each other and are surely +aware of each other's presence in bare, flat areas. These facts +suggest that no social hierarchy exists in _T. ornata_. On one +occasion an adult male and a juvenile (hatched the previous autumn) +were found foraging next to one another on the same pile of cow dung. + +When an individual became motionless in an attitude of wariness after +having detected me in my blind, its behavior evoked no response on the +part of other turtles, a few feet away. + + + + +INJURIES + + +Fire, freezing, molestation by predators, and trampling by cattle or +native ungulates are only a few natural sources of injury to which box +turtles have always been exposed. Man's civilization in the Great +Plains, chiefly his automobile and other machines, have compounded the +total of environmental hazards. Automobiles now constitute a major +cause of death and serious injury to box turtles. Each year thousands +are struck on Kansas highways alone, not to mention the many +casualties resulting from mowing machines, combines, and other farm +machinery. + +Although grass fires usually occur in early spring or late fall when +box turtles are underground, some turtles are surely killed by fires +and many are injured. In early April of 1955 the pasture at the Damm +Farm was burned. Similar burnings, I discovered, had occurred both +intentionally and accidently in past years at irregular intervals. No +deaths or injuries, attributable to fire were discovered in the course +of intensive field work in the spring and summer of 1955, when the new +grass was short and conditions for finding and marking box turtles +were ideal. Badly burned individuals, if any, may have secreted +themselves until their wounds had healed. In June, 1957, an adult +female, that had been burned severely, was taken from a small puddle +in a ravine on the Damm Farm. The soft parts of her body, excepting +her head and neck, were a nearly solid mass of smooth scar tissue, the +scales and rugosities of the skin being practically obliterated. The +tail was reduced to a mere knob surrounding the anus and dead, exposed +bone was visible on most of the dorsal part of the carapace. Possibly +this female was burned in the fire of 1955. Lack of injury to the head +and neck can probably be accounted for by the additional protection +afforded these parts by the folded forelegs when the turtle was +withdrawn in the shell. + +Turtles that are smashed flat on the highway, of course, have no +chance of survival. Highway fatalities are usually the result either +of "direct hits," where the tire of a vehicle passes directly over the +turtle, or of repeated pummeling by subsequently passing vehicles. The +writer, while driving behind other cars that struck turtles or by +sitting beside roads, has observed numerous turtle casualties. Most +are struck a glancing blow by a tire and are propelled some distance +through the air or on the surface of the pavement, often to the side +of the road. Such a blow is usually sufficient to crack or chip the +shell, or at least to scuff away parts of the epidermal covering. +Turtles, so injured, usually survive. + +Parts of the shell do not break away easily, even when several deep +cracks are present, and only a little bleeding occurs. A common injury +inflicted on the highway is the wrenching and subsequent dislocation +of the carapaco-plastral articulation. In such instances the +ligamentous tissue joining the two parts is torn extensively. Under +these circumstances the movable shell parts seem to act as a safety +device, giving way under pressure that would crack the shell of a +turtle with rigid, fixed buttresses. Dislocations of the +carapaco-plastral articulation that have healed are characterized by +abnormally heavy development of ligamentous tissue, which may +elaborate a horny, scutelike substance on its outer surface. + +The extent to which serious injury incapacitates a turtle is not +known. Surely open wounds are susceptible to infection and to various +kinds of secondary injury; normal activity is probably interrupted by +a period of quiescence, at least in the period of initial healing. + +An injured female had a hole, slightly more than one inch in diameter, +in the right side of the carapace at the level of the second lateral +lamina. A tight, thin membrane stretched between the broken edges of +the opening; this membrane contained no bone and was covered +externally by scar tissue. It was obvious that this turtle had +recovered, at least in part, from a serious injury (inflicted probably +by a piece of heavy farm machinery). + +Minor chips, scratches, and abrasions on the shell result from a +variety of sources, some of them mentioned above. Small rounded pits +in the bony shell (shell pitting) due to causes other than mechanical +injury, are found in nearly all kinds of turtles according to +Carpenter (1956), Hunt (1957), and my personal observation. In _T. +ornata_, however, the condition is less common than in the specimens +of _T. carolina_ described by Carpenter and in the remaining species +of _Terrapene_ that I have examined. + +Carpenter (1956:86) came to no conclusion as to the cause of shell +pitting in _Terrapene carolina_ but suggested that a variety of +factors including parasitic fungi, parasitic invertebrates, and simple +shell erosion, might be responsible. + +According to my own observations on turtles in the University of +Kansas collections, shell pits range in size and shape from shallow, +barely discernible depressions to deep borings; I suspect that shell +pitting for turtles in general has many causes, some of which may be +of more frequent occurrence in one species than in another. + +Hunt (1957:20) presumably was referring to shell pitting by a more +suitable name when he wrote of, "... necrosis ... of mycotic origin." +Hunt (_loc. cit._) stated that "Of those cases which have been +recently examined, the author found all were due to the invasion of +Mucorales beneath the plates of the epidermal laminae. This disease is +of extremely common occurrence and has been found in all members of +the order but is seldom found in marine species. Mycosis more +frequently occurs on the plastron than on the carapace." Hunt +presented no evidence to support his statement regarding invasion of +the shell by Mucorales. + +Evidence that injury to the soft parts of the body is also fairly +common is seen in the many _T. ornata_ with missing feet and legs. +Stumps resulting from amputations are covered with tough, calloused +skin and sometimes by horny tissue similar to that of the antebrachial +scales. Amputees are incapacitated only slightly in normal locomotion +if a functional stump remains; probably a cripple is somewhat +handicapped in other functions, such as burrowing, nest digging +(females), and copulation (males). Causes of amputation are discussed +in the section on predators. + +Fractures of the limb bones are common. A female from Stafford County, +Kansas (Pl. 29, Fig. 4), showed a typical case of fracture and +subsequent repair; the right fibula had been broken and the ends +dislocated; a great mass of bone joined the repaired break to the +middle of the tibia, giving the entire skeleton of the leg the +appearance of the letter "H." The fibula, shortened by the +dislocation, no longer articulated by its proximal end with the femur; +the tibia probably bore the entire load in the period of repair and +the transverse connection that formed between the bones later took +over the function of the fibula. + +There is little doubt that ornate box turtles are stepped on or +trampled by cattle, at least occasionally, but I never observed such +an incident; the predilection of ornate turtles for dung insects and +for moving along cattle pathways brings them to close quarters with +cattle and probably did likewise with native ungulates. A steer, +stepping on a box turtle, could inflict superficial damage to the +shell or cause broken limbs but would probably not crush the turtle +unless on a hard substrate. + + + + +REPAIR OF INJURIES TO THE SHELL + + +Most adults and a few juveniles examined in the field and laboratory +had one or more small injuries on the carapace that had healed or were +undergoing repair. Such injuries almost never occurred on the +plastron. In an injury that was undergoing repair, a small piece of +smooth, whitened bone was exposed where a piece of epidermis was +missing from the shell. One or more edges of the exposed bone +characteristically projected over the surrounding epidermis, making +the bone appear as though it had been driven forcefully, like a +splinter, into the shell (Pl. 29, Figs. 1 and 2). Because of their +curious appearance, small areas of repair were referred to in my notes +as "splinter scars." The position and number of splinter scars were +often recorded as supplementary means of individualizing turtles in +the field. + +Splinter scars result from minor abrasions that damage a few square +millimeters of the shell. Larger areas of exposed bone were noted in +only a few specimens. Two turtles at the Damm Farm had bone exposed on +more than one-half the surface area of the carapace; both of these +turtles were probably burned in the grass fire of 1955. Ordinarily, a +break in the shell does not induce extensive regeneration of tissues; +when shells are damaged by crushing or cracking, regeneration of +epidermis and bone occurs only along the lines of fracture, unless the +broken parts have been dislocated. Ligamentous tissue develops in some +breaks on the plastron, the broken area remaining slightly movable +after healing is completed (Pl. 24). + +Dissection of injured shells revealed the mode of shell regeneration +to be the same whether a large or small portion of the shell had been +damaged. An abrasion may gouge out a small portion of the shell; +burning, freezing, or concussion may kill a portion of the epidermis +and a corresponding portion of bone beneath it without actually +disfiguring the shell. Dead bone and epidermis become loosened at the +margin of the wound. The epidermis sloughs off soon afterward but the +bone adheres to the wound. New epidermis and new bone, growing from +undamaged tissues at the edges of the wound, encroach on the wound +beneath the layer of dead bone. The piece of dead bone is thereby +gradually isolated from the rest of the shell and is sloughed off when +healing is complete. The dead bone may come off in one piece or slough +off gradually at its edges as healing proceeds toward the center of +the wound. The layer of dead bone protects the wound during the +process of regeneration (Pl. 30). Areas of exposed bone become white +and shiny, nearly enamellike in appearance, as a result of wear on the +shell. + +The above conclusions, in regard to _T. ornata_, agree basically with +the findings of Woodbury and Hardy (1948:161-162) and Miller +(1955:116) on regeneration of the shell in desert tortoises (_Gopherus +agassizi_). Danini (1946:592-4, English summary) made histological +studies on regeneration of the shell in specimens of _Emys +orbicularis_; he found that new bone trabeculae formed on the surfaces +of undamaged trabeculae at the edge of the wound and formed also in +connective tissue at the center of the wound. Regeneration of bone was +incomplete in some instances where total extirpation of a portion of +the shell had occurred. Regenerated epidermis was usually thicker than +the original scute. + +Exposed bone on the shells of turtles that have been injured in fires, +although dead, is unmarked and shows no evidence of being burned. +Exposure to fire kills the growing portions of both the epidermis and +the bone but seemingly does not actually char or disfigure the bone +(although the epidermis may be so affected) (Pl. 29, Fig. 3). Injuries +from fire result probably from brief encounter with the fire itself or +from more prolonged contact with some surface heated by the fire. A +turtle that remained in a fire long enough to have its shell charred +would presumably have little chance of survival. Grossly disfigured +shells therefore do not result directly from burns but are due to the +gnarled texture of the regenerated bone and epidermis remaining after +the dead portions of the shell have been sloughed off. Information on +injuries from fire was supplemented by examination of several badly +burned specimens of _T. carolina_. Their shells were nearly covered +with exposed bone and regenerated epidermis. One specimen was so badly +damaged that the entire anterior rim of its carapace was loose and +could be pulled away easily to disclose a gnarled mass of regenerating +bone beneath it (Pl. 29, Fig. 3). There were areas near the posterior +margin of the carapace of each specimen where regenerated epidermis +was evident but where the bone was seemingly uninjured; the +regenerated epidermis was nearly transparent. + +Areas of regenerated epidermis on specimens of _T. ornata_ were rough +in texture and slightly paler than the surrounding scutes. +Color-pattern is not reproduced in the process of regeneration but +irregularly shaped light blotches sometimes occur in the places where +radiations or other distinct markings formerly were present. A slight +depression remains on the shell after regeneration is completed. I +suspect that small injuries may be repaired in the course of a single +growing season but that injuries involving a large part of the shell +may take several years to heal completely. Cagle (1945:45) reported +that a bullet wound in the shell of a painted turtle (_Chrysemys +picta_) healed completely in approximately 23 months. Danini (_loc. +cit._) found that regeneration of the shell in _Emys orbicularis_ was +complete in as short a time as 225 days. Woodbury and Hardy (_loc. +cit._) stated that small injuries to the shell of _Gopherus agassizi_ +may take as long as seven years to heal. + + + + +ECTOPARASITES + + +Two kinds of ectoparasites were found on ornate box turtles in the +course of the present study; larvae of chigger mites (_Trombicula +alfreddugesi_) were abundant on specimens collected in summer and, +larvae of the bot fly (_Sarcophaga cistudinis_) were found on +specimens throughout the season of activity, and, in a few instances, +on hibernating turtles. In general, these ectoparasites do little or +no harm to ornate box turtles, although heavy infestations may cause +temporary interruption of normal activity or may even cause occasional +death. + +Concerning the larvae of _T. alfreddugesi_, Loomis (1956:1260) wrote, +"In northeastern Kansas, larvae become numerous in early June (shortly +after they first appear), increase in numbers to greatest abundance +throughout late June and July, decrease slightly in August, become +markedly reduced in September, and only a few larvae (mostly on hosts) +remain in October and early November." He considered _T. alfreddugesi_ +to be the most abundant chigger mite in Kansas and stated (_op. +cit._:1265) that it is most common "... in open fields supporting good +stands of grasses, weeds and shrubs, and where moderate to large +populations of vertebrates are present." Loomis listed ornate box +turtles (_op. cit._:1261-2) as important hosts of _Trombicula +alfreddugesi_ but noted that box turtles are not so heavily infested +as are certain other reptiles. The two other species of chigger mites +that Loomis (_op. cit._:1368) found on _T. ornata_ in Kansas (_T. +lipovskyana_ and _T. montanensis_) were not found in the present +study. + +Box turtles were considered to have chigger infestations when the +reddish larvae could be detected with the unaided eye. No chiggers +were seen on turtles in the period from spring emergence until June +13, 1955. On the latter date a few scattered chiggers were noted on +several individuals and it was on this same date that the writer +received his first "chigger bites" of the year. Numbers of chiggers +increased in the latter half of June and heavily infested turtles were +noted throughout July. No chiggers were seen on box turtles after +mid-September in 1955. + +Chiggers were ordinarily found only on the soft parts of the turtles' +bodies. Early in the season infestations were chiefly on the head and +neck. Favorite sites of attachment were the point where the skin of +the neck joins the carapace and on the skin around the eyes. Later in +the season some chiggers could be found on nearly every part of the +body where soft skin was present; concealed areas of skin, such as the +axillary and inguinal pockets, the anal region, and the inner rim of +the carapace (where it joins the skin of the body), harbored +concentrations of chiggers. Juveniles were relatively more heavily +infested than adults and, even early in the season, had chiggers +attached along many of the interlaminal seams of the shell. Broad +areas of soft, newly-formed epidermis on the shells of juveniles +probably afforded a better place of attachment to chiggers than did +the interlaminal seams of adults. The interlaminal seams and +transverse hinges of adults were not infested until the height of the +season of chigger activity. Heavily infested adults, observed in early +July, were literally covered with chiggers; red larvae outlined nearly +all the scutes of the shell, the anus, the mouth, and the eyes. When +turtles were picked up for examination, chiggers could be seen moving +rapidly from one interlaminal seam to another. + +Box turtles kept in outdoor pens and in the laboratory did not long +maintain visible infestations of chiggers, even during the time in +summer when turtles found in the field were heavily infested. + +A four-year-old juvenile was found nearly immersed in the shallow +water of a pond on July 4, 1955; its right eye had been damaged by an +especially heavy concentration of chiggers. When I released the +turtle, some 50 feet from the pond, it returned to the water and spent +the next four days there. The turtle was probably in a period of +quiescence induced by the eye injury and the heavy infestation of +chiggers; immersion in water could be expected to help free the turtle +of chiggers and to relieve trauma resulting from the injured eye. +Richard B. Loomis told me that larval chiggers are able to survive +under water for several days but that warm water will hasten their +demise. + +Infestations of larval bot flies (_Sarcophaga cistudinis_) were noted +in several turtles at the Damm Farm and, upon closer scrutiny, were +found to be common in preserved specimens from other areas. Larvae +were always found in flask-shaped pockets (Pl. 27, Fig. 2) beneath the +skin; the pockets opened to the outside by a small hole, the edges of +which were dried and discolored. One larva sometimes protruded from +the opening. The inside of the pocket is lined with smooth, skinlike +tissue. Heavily infested box turtles may have four or five such +pockets, each containing one to many larvae. The most frequent sites +of the pockets are the skin of the axillary and inguinal regions, and +the skin of the limbs and neck, especially near the bases of these +members. Subadults were more heavily infested than older adults; no +infestations of hatchlings or small juveniles were noted. + +An adult female, infested with bot fly larvae when she was removed +from her hibernaculum in late October, 1955, bore no trace of larvae +or of the pocket that had contained them when she was recaptured the +following June. According to Rokosky (1948), the larvae eventually +fall to earth and pupate. The individuals of _T. carolina_ studied by +him were not re-infested by adult bot flies; one turtle ate some of +the larvae that dropped from its body. + +The manner in which box turtles are infested by bot fly larvae is +uncertain. Possibly the eggs are picked up accidentally or laid on the +skin while box turtles are foraging in dung. Belding (1952:841) +classifies the genus _Scarophaga_ as semi-host-specific, depositing +eggs in open wounds. + +McMullen (1940), Rodeck (1949), and Rainey (1953), described +individuals of _T. ornata_ parasitized by _S. cistudinis_. Rokosky +(1948) and Peters (1948:473) reported infestations in _T. carolina_. +Infestations were the cause of death in the instances noted by Rainey +and Rokosky. + + + + +PREDATORS + + +Few first-hand observations on predators of _T. ornata_ are available +and I have found little direct evidence of predation in the course of +this study. In general, adults of the species seem to have few natural +enemies other than man. Several of my colleagues at the University of +Kansas have observed dogs carrying box turtles in their mouths or +chewing on them. Frank B. Cross told me his dog caught and ate young +_T. ornata_ in Payne County, Oklahoma, and A. B. Leonard once saw a +badger carrying one in Dewy County, Oklahoma. At the Reservation, a +freshly killed juvenile was found beneath the nest of a crow (_Corvus +brachyrhynchos_) and remains of a hatchling were found in a scat of a +copperhead (_Agkistrodon contortrix_). + +Dr. Fred H. Dale, Director of the Patuxent Research Refuge, Laurel, +Maryland, kindly furnished photostatic copies of cards, from the +Division of Food Habits Research of the U. S. Fish and Wildlife +Service, recording the instances in which _Terrapene ornata_ was +listed as a food-item. In one instance the stomach of each of two +nestlings, in the same nest, of the White-necked Raven (_Corvus +cryptoleucus_) in Terry County, Texas, contained remains of recently +hatched ornate box turtles; the remains of one turtle made up 64 per +cent of the contents of one stomach, and parts of three turtles made +up 80 per cent of the contents of the other stomach. Each of two +stomachs of the coyote (_Canis latrans_) from Quay County, New Mexico, +contained a "trace" of ornate box turtle. + +Wild carnivores known to occur on the Damm Farm were raccoons +(_Procyon lotor_), striped skunks (_Mephitis mephitis_), badgers +(_Taxidea taxus_), and coyotes (_Canis latrans_); all were suspect as +predators of ornate box turtles. + +On December 10, 1953, ten dead box turtles (eight adults and two +juveniles) were discovered at the top of a cut bank on the Damm Farm, +within a few feet of a burrow that was used at least part of the time +by a striped skunk. The condition of the turtles suggested that they +had lain in the open for several weeks. The heads and legs were +missing from most of the turtles and tooth marks were discernible on +several of the shells. A logical explanation of this occurrence is +that the turtles, using the burrow as a hibernaculum, were ousted by a +predator that also inhabited the burrow. Turtles moving about +sporadically in late autumn may be quickly chilled by a sudden drop in +temperature and therefore be more susceptible to predation than at +other times of the year. Two of my colleagues at the Museum of Natural +History informed me that they had observed similar concentrations of +dead _T. ornata_ in winter. + +In July, 1952, H. B. Tordoff collected eight shells of juvenile _T. +ornata_ in a dry creek bed near Sharon, Barber County, Kansas. Some of +the shells had small tooth-punctures. The stream bed habitat and the +appearance of the tooth punctures tended to incriminate raccoons as +predators. Raccoons, more than any other carnivore mentioned above, +possess the manual dexterity necessary to pry open the shell of a box +turtle and bite away the soft parts. Badgers and possibly coyotes are +probably the only local carnivores (excluding large dogs) that could +crack open the shell of an adult turtle by sheer force. + +Adults of _T. ornata_, since they occasionally molest small juveniles, +must be considered in the category of predators. When captive adults +and juveniles were fed from the same container in the laboratory, the +turtles occasionally bit one another accidently. Serious injury to the +young was prevented by watching the adults closely and moving them +away when they caught a smaller turtle by the leg or head. Similar +accidents presumably occur in nature; juveniles and adults were +sometimes found feeding side by side. William R. Brecheisen told me +that adults kept in a stock tank at his farm in the summer of 1955 +regularly and purposefully chased and bit small juveniles in the same +tank. Brecheisen gave me a juvenile that had been so bitten; the right +side of its head was badly damaged (the eye gone and a portion of the +bony orbit broken) but was partly healed. Ralph J. Donahue told me +that he saw an adult _T. ornata_ attack a juvenal _T. carolina_, and +provided a photograph of the incident. The juvenile was not injured. + +Although small box turtles may occasionally be caught and killed by +adults in nature, this seems not to constitute a major source of +predation on the young. + +Other animals that may prey upon young box turtles occasionally (and +that were known to occur at the Damm Farm) are bullsnakes (_Pituophis +catenifer_), red-tailed hawks (_Buteo jamaicensis_), marsh hawks +(_Circus cyaneus_), crows (_Corvus brachyrhynchos_), and opossums +(_Didelphis marsupialis_), and domestic cats. + +Nest predators probably have greater effect on populations of _T. +ornata_ than do predators of hatchlings, juveniles, and adults. Four +robbed nests were found at the Damm Farm; in each instance, striped +skunks were thought to be the predators. E. H. Taylor told me that he +once saw a bullsnake swallow an entire clutch of newly laid eggs +before the female turtle could cover the nest. + + + + +DEFENSE + + +Box turtles rely for protection on the closable shell and on +inconspicuousness; defense reactions, except in the rare instances +that biting is provoked, are purely passive. + +Box turtles handled in the course of field work varied widely in their +reactions. Many struggled violently when being measured or marked +whereas others were completely passive, closing the shell tightly and +making it difficult for me to examine the soft parts of the body. +These differences in behavior did not seem to be correlated either +with sex or with age; generally lessened activity was associated with +suboptimum body temperatures. All box turtles found in the field were +extremely wary. As soon as one sighted me (sometimes at a distance of +200 feet or more), it became motionless with shell raised from the +ground and neck extended (Pl. 28, Fig. 5). Some turtles remained in +this motionless stance for half an hour or more, finally moving slowly +away if I remained motionless. Turtles made no attempt to escape until +I approached them closely or until they were in danger of being +trampled by my horse; they would then move away with remarkable +rapidity. Box turtles seemed unaware of an intruder until he could be +seen or until he touched the turtle. When a turtle was approached from +the rear, whistling, finger snapping, and normal footfalls did not +attract its attention. Latham (1917:16) observed corresponding +behavior in _T. carolina_. Wever and Vernon (1956) found the ear of +_T. carolina_ to be keenly sensitive to sounds in the range of 100-600 +cycles per second but progressively less sensitive to sounds of higher +and lower frequencies. Surely a predator as stealthy as a coyote could +approach a box turtle unseen and could quickly bite off at least one +of the turtle's legs. Many of the mutilated box turtles that I +observed may have survived such encounters with carnivores. The +tendency of some individuals, when handled, to over-extend the limbs +and neck (rather than closing the shell) in an attempt to escape, +would make them easy victims for any predator. + +Ornate box turtles were kept in my home, along with several cats. +Initial behavior was characterized by mutual wariness; subsequently +the cats would follow a turtle about the house for a time, +occasionally pawing at an exposed limb. The turtles withdrew only when +touched or when approached from the front. After a day or two the cats +and turtles ignored each other, often eating and drinking from the +same dishes without incident. Under these circumstances the cats, I +believe, could easily have killed or injured the turtles. A turtle +would occasionally gain the respect of a cat by biting it. + +The strong odor sometimes given off by box turtles is produced by the +secretions of four musk glands, two situated anteriorly on each side +and opening by small, nearly invisible apertures beneath the fourth +marginal scute. According to Hoffman (1890:9), two other musk glands, +opening beneath the eighth marginal scute on each side, are also +present in _Terrapene_; these posterior glands were not found in the +several specimens of _T. ornata_ that I dissected. + +Strong odors were produced by nearly all small juveniles until they +became accustomed to being handled. Older juveniles and adults +produced strong odors only in response to pain or injury, as, for +example, when they were killed in the laboratory prior to preservation +or when they were being marked in the field. Young box turtles were +capable of producing strong odors as soon as they hatched. + +Norris and Zweifel (1950:3) considered the odor produced by _T. o. +luteola_ to issue from the "... concentrated, highly pungent +urine...." voided by individuals when they were disturbed, and thought +the production of odor to be a defense mechanism. Neill (1948b:130) +reported that hatchlings of _T. carolina_ with unhealed umbilical +scars emitted a musky odor comparable to that of the stinkpot, +_Sternotherus odoratus_; he thought the capacity to produce this odor +was lost at about the time that the plastral hinge became functional. + +The function of musk glands in _Terrapene_ and, in all other turtles, +is unknown. Since biting and nuzzling of the edges of the shell is an +integral part of the courtship of many turtles, odor produced by the +musk glands may well be a means of social recognition or of sexual +stimulation. Repellant odor may have a protective value in young box +turtles but it is unlikely that larger predators would be frightened +away or even discouraged by odor alone. In this respect Neill (_loc. +cit._) and I concur. + + + + +DISCUSSION OF ADAPTATIONS + + +Most of the morphological characteristics distinguishing box turtles +from other North American emyid turtles, the most notable of which is +the movable plastron, are modifications that have evolved as a result +of selectional pressures favoring adaptation to more or less +terrestrial existence. Similar adaptations have arisen independently +in several branches of the emyid stock (see introduction). The genus +_Terrapene_ seems to have departed farther from a generalized emyid +form than have other kinds of box-turtle-like chelonians. In a +morphological sense, _Terrapene ornata_ is clearly the most +specialized member of its genus now occurring in the United States +(my own studies have revealed that populations in western Mexico now +referred to as _T. klauberi_ and _T. nelsoni_ are as specialized as +_T. ornata_ in some respects but more generalized in others). The +present ecological study has demonstrated that _T. ornata_ is +specialized in habits as well as in structure. It is concluded that +these specializations (of more generalized and perhaps more primitive +conditions as, for example in _T. carolina_) constitute adaptation for +terrestrial existence in open, semiarid habitats. These adaptations in +_T. ornata_ have resulted, in a few instances, in unique habits and +structures; however, in most instances the adaptations have produced +slight but recognizable changes that are definable only by degree of +difference from other species of box turtles. + +The closable shell of box turtles is of obvious survival value in +providing protection for the soft parts of the body. In most of the +species of _Terrapene_, the lobes of the plastron completely close the +openings of the shell; closure is so tightly effected in some +individuals that it is difficult to insert the blade of a knife +between the adpressed margins of carapace and plastron. In _T. ornata_ +nevertheless, both lobes of the plastron are deficient on their +lateral margins; four narrow openings remain when the lobes are drawn +shut. Emargination of the plastron has occurred at the places where +the limbs rub against it during locomotion. This reduction of the +plastron permits the body to be held off the ground during forward +locomotion and seemingly permits a generally freer range of movement +for the limbs. The possible disadvantages of an imperfectly closable +shell seem to be compensated for by increased mobility. Reduction of +the plastron is correlated with a general lightening of the shell, +probably associated with the increased vagility of this species. +Lightening of the shell is evident also in the relatively thin, +loosely articulated bony elements. Shells of adult _T. ornata_ that +are old and weathered, or macerated (unless they are partly +co-ossified because of injury), can nearly always be disarticulated +with ease, whereas the bony elements in the shells of adult _T. +carolina_ (all races) are nearly always co-ossified or separable only +after prolonged maceration. + +The relatively low, flattened shell of _T. ornata_ is an adaptation +associated with the tendency to seek shelter in the limited space of +earthen forms, burrows, or small natural cavities in the course of the +warm season and to burrow more deeply into the ground in winter. +_Terrapene ornata_ is, in fact, the only species of the genus that may +be considered an habitual burrower. Individuals of _T. carolina_ tend +to seek shelter in the warm season by making forms in dense vegetation +or by digging into yielding substrata such as mud or humus, although +they may burrow deeply into the earth in winter. Extreme weakness or +absence of the middorsal keel of _T. ornata_ seems to be a +modification associated with burrowing habits and general adaptation +to terrestrial life; the keel is similarly reduced in testudinids. + +Retention of epidermal laminae (as opposed to regular exfoliation of +the older parts of scutes) occurs in all box turtles, in several other +groups of terrestrial emyids, and in testudinids. The phenomenon is +here considered to be a specialization of scute shedding--developed in +terrestrial and semiterrestrial chelonians--that provides additional +protection to the shell against wear and minor injuries. + +General shortening of digits--the result of reduction in number of +phalanges as well as in their length, and to a lesser degree the +shortening of metapodial elements--has occurred in several groups of +chelonians with terrestrial tendencies (the opposite--lengthening of +phalanges and metapodials, and hyperphalangy--has occurred in certain +groups that are highly aquatic). The pes of box turtles has remained +relatively unchanged in this respect; a few phalanges on the lateral +digit have been lost (especially in three-toed forms), but little +reduction in length has occurred. The chief modification of the pes is +a general narrowing brought about by the tendency of the digits to be +crowded together, one on top of the other, rather than spread in a +horizontal plane. Considerably more modification is seen in the manus +of _Terrapene_. Phalangeal formulae (expressing the number of +phalanges from the first digit outward) range from 2-3-3-3-2 +(primitive in _Terrapene_) to 2-3-3-2-2 in the races of _carolina_ and +have the same range in the species of eastern Mexico. Extreme +reduction in number (2-2-2-2-2) as well as general shortening of +phalanges occurs in _T. ornata_. The formula is the same in the one +specimen of _T. klauberi_ that has been skeletonized. This +modification of the forelimb in _T. ornata_ has produced a more rigid, +stronger manus that is well adapted to the requirements of burrowing +and to locomotion over unyielding substrata. Shortening of the manus +(and, to a lesser extent, the pes) has been accompanied by reduction +and loss of interdigital webbing. It is noteworthy that _T. ornata_ +has achieved the same reduction in number of phalanges as _Gopherus_, +which displays the extreme of specialization in this respect among +North American turtles. The manus in _T. ornata_ is not shortened so +much as in _Gopherus_. + +The first toe in males of _T. ornata_ is uniquely widened, thickened, +and inturned. Males of some other species of _Terrapene_ have greatly +enlarged rear claws, some of which turn slightly inward, but none has +the flexed first toe hooklike as it is in _ornata_ (a modified first +toe, resembling that described for _T. ornata_, has been observed in a +live male of _T. klauberi_ [now KU 51430] since the preparation of +this manuscript). In males of _T. ornata_ the penultimate phalanx of +the first toe has a normal, vertical articular surface on its proximal +end. However, the distal articular surface (when viewed from the +distal end of the phalanx) has its axis rotated away from the vertical +plane approximately 45 degrees in a counterclockwise direction. As the +foot is pronated and extended, and as the digits are flexed, there is +a concomitant inward rotation of the first metatarsal at its proximal +joint; this rotation, combined with the divergent planes of the +articulating surfaces on the penultimate phalanx, cause the ungual +phalanx to be flexed at right angles to the inner side of foot, in a +plane perpendicular to that of the other toes (Fig. 21). + +The precise function of the modified first toe of males is unknown, +although it is reasonably safe to assume that the modification is +closely associated with clasping during coition. In the matings that I +observed, the inturned first claw of the male secured a hold on the +female's rump or just beneath her legs, whereas the remaining three +toes gripped the edge of her plastron. The combined hold, on shell and +skin, clearly affords the male a more secure position during coitus +(whether the female clasps his legs with hers or not) than would a +hold on skin or shell alone. Possibly intromission can be maintained +in this position even when the female is attempting to escape. In +males the plastron is less concave in _T. ornata_ than in _T. +carolina_. Furthermore, males of _T. ornata_ are, on the average, +smaller than females, whereas the reverse is true in _T. carolina_. +Possibly the ability of the male to secure an especially firm grip on +the female enhances the probability of small males mounting and +inseminating larger females, whereas successful matings might +otherwise be limited to pairs in which the male was the larger member. + +It is worthy of note that turtles of the genus _Terrapene_ are +seemingly the only North American emyids that carry out the entire +process of mating on land; other, semiterrestrial emyids (for example, +_Clemmys insculpta_ and _Emydoidea blandingi_) return to water for +actual coition, although the precoital behavior sometimes occurs on +land. + +Nearly all gradations from a fully developed zygomatic arch to a +greatly reduced arch can be observed in skulls of the various species +of _Terrapene_ (Fig. 2) (Taylor, 1895:586, Figs. 2-7). The highest +degree of reduction is achieved in _T. ornata_ and _T. klauberi_, both +of which lack the quadratojugal bone and have no zygomatic arch +whatever (except for an occasional, poorly defined anterior vestige +formed by the postfrontal, the jugal, or both). Reduction of the +zygoma clearly represents modification of a more generalized, complete +arch. As yet there is no clear evidence that reduction of the +zygomatic arch is of adaptive value. It is noteworthy, however, that +similar reduction of the arch has occurred independently in a number +of emyid and testudinid groups, nearly all of which have terrestrial +or semiterrestrial habits. Although discussion of phyletic lines in +_Terrapene_ is beyond the scope of this report, I tentatively suggest +that reduced zygomatic arches have arisen independently in more than +one group of _Terrapene_ and that similar reduction of the arch in two +species of the genus does not necessarily indicate an especially close +relationship of such species. + +In a recent survey of cloacal bursae in chelonians, Smith and James +(1958:88) reported _T. ornata_ and _T. mexicana_ to be among the few +emyids that lacked these structures; in the opinion of the authors +(_op. cit._:94) cloacal bursae evolved in chelonians that required an +accessory respiratory organ for long periods of quiescence +(hibernation or aestivation) under water, and were secondarily lost in +terrestrial forms that hibernated on land. The assumption is a +reasonable one, at least in regard to emyids and testudinids. Lack of +cloacal bursae in _T. ornata_ and in all testudinids, can be +correlated with the completely terrestrial habits of those turtles. +Cloacal bursae seem to be vestigial in the species of _Terrapene_ +possessing them and to be of little or no use as respiratory +structures (except perhaps in _T. coahuila_). + +In most of the species of _Terrapene_ the carapace has a pattern of +pale markings on a darker background; however, unicolored individuals +are the rule in certain populations (for example, at the western edge +of the range of _T. carolina_ and in _T. ornata luteola_) and occur as +occasional variations in other populations (in _T. yucatana_, _T. +mexicana_, and, throughout the range of _T. carolina_, albeit more +commonly in the southeastern part of the range). Personal observation +of interspecific and ontogenetic variation of color patterns of box +turtles has convinced me that a basic pattern of more or less linear +radiations is the one from which all other patterns (including spots, +blotches, rosettes, and the unicolored condition) can be derived, and, +that the radial pattern is generalized and primitive for _Terrapene_ +(possibly for all emyids and testudinids as well). In the light of +this conclusion, the radial pattern of _T. ornata_ may be considered +generalized. I suspect, however, that the pattern of a living species +most closely approaching that of the primitive ancestral stock of +_Terrapene_ is the pattern of fine, wavy, dark radiations (on a paler +background) present in young examples of _T. coahuila_. + +Box turtles in general have lower reproductive potentials (as +indicated by fewer eggs and longer prepuberal period) than do most +aquatic emyids. This low potential seems to be compensated for by a +lower rate of postnatal mortality (especially in adults) due to the +protection afforded by the closable shell and the ability to recover +from serious injury. _Terrapene o. ornata_ and _T. c. carolina_ are +the only box turtles the life histories of which are known well enough +to permit significant comparison. The reproductive potentials of _T. +o. ornata_ and _T. c. carolina_ seem to be much the same. + + + [Illustration: PLATE 15] + + Aerial photograph of Damm Farm (July, 1954). + + Numbers and letters on photograph denote the following: + 1. Main pasture with subdivisions + a to c, respectively, northwest corner area, + house pond area, and southern ravine area; + 2. Wooded area; and, + 3. Cultivated area. + + + [Illustration: PLATE 16] + + FIG. 1. A water-filled ravine in the northern part of the + pasture at the Damm Farm (June 28, 1958). The subdivision of + the pasture referred to in text as "northwest corner area" can + be seen sloping into the ravine from the west (left + background). + + FIG. 2. A cow path leading southward away from a ravine, at the + Damm Farm (June 28, 1958). Ornate box turtles used such paths + as routes of travel in the course of their daily activities. + + + [Illustration: PLATE 17] + + FIG. 1. Grassland on crest of hill at Damm Farm with + northeastern corner of main pasture in background (June 29, + 1958). + + FIG. 2. A bare area along the rock fence at northern edge of + pasture at Damm Farm. Ornate box turtles could nearly always be + found foraging in cow dung here and in similar areas along + other fences (June 28, 1958). + + + [Illustration: PLATE 18] + + FIG. 1. A ravine in the southern part of the pasture at the + Damm Farm (June 28, 1958). Small springs at the heads of such + ravines produced marshy conditions at their bottoms and + provided drinking water, in the form of shallow pools, for box + turtles for at least part of the year. Banks of ravines + provided suitable sites for the construction of nests and + forms. + + FIG. 2. A mulberry tree on the bank of a ravine near northern + edge of Damm pasture (June 28, 1958). Box turtles frequented + the area beneath the tree when fruit fell to the ground in June + and July. The ravine shown here filled with water after being + dammed in June, 1956. + + + [Illustration: PLATE 19] + + Representative stages in the spermatogenic cycle of + _T. o. ornata_ (all specimens obtained in Douglas County, + Kansas, 1955). + + FIGS. 1 to 5, respectively, are sections of seminiferous tubules + obtained on May 17, June 14, July 15, Aug. 31, and Oct. 4. + FIG. 6: seminiferous tubule of immature male (plastral length, + 88 mm.), six years old, obtained on June 30. + FIG. 7: section of epididymis from mature male obtained on + April 17, three days after turtle emerged from hibernation; + mature sperm form a continuous dark mass in center of + epididymis. + FIG. 8: sperm in uterine portion of oviduct of female obtained on + April 18, 1954. + + Figs. 1 to 6 and 8 were photographed A-- 430, and were enlarged + 1.4 times. Fig. 7 was photographed A-- 35, and was enlarged + 1.4 times. + + + [Illustration: PLATE 20] + + FIG. 1. Left ovary of mature female, prior to ovulation, + May 15, 1956 (A-- 1). + FIG. 2. Fresh corpus luteum, June 2, 1956 (A-- 4A1/2). + FIG. 3. Testes of mature male, August 31, 1955 (A-- 1). + FIG. 4. Testes of mature male, April 14, 1956 (A-- 2). + FIG. 5. Left ovary of subadult female (seven years old, plastral + length, 114 mm.) that would have matured in approximately one + year (A-- 1A1/2). + FIG. 6. Left ovary of juvenal female (11 years old, plastral length, + 95 mm., A-- 1A1/2). + + + [Illustration: PLATE 21] + + FIG. 1. A trial nest cavity excavated by a gravid _T. o. ornata_ + at the Damm Farm on June 8, 1956. The cavity was situated at + the edge of a grassy area on the upper rim of a ravine + embankment. Twelve-inch ruler shows scale. + + FIG. 2. A depression, resulting from an old post-hole, showing + the openings made by three box turtles as they left their + hibernacula in April, 1956 (photographed May 15, 1956). + Twelve-inch ruler shows scale. + + + [Illustration: PLATE 22] + + FIG. 1. Right abdominal lamina (A-- 2A1/2) of a four-year-old + juvenal male showing method of measuring growth-rings. The + last growth-ring (4) was formed at the end of the 1954 growing + season. The first growth-ring (H) marks the end of the season + of hatching (1950). The umbilical scar (U) is faintly visible. + The growth-zone for 1955 (specimen captured June 23) is just + beginning to show in interlaminal seam. + + FIG. 2. + _Left_--Right abdominal lamina (A-- 2) of subadult female, eight + years old. The last growth-zone was formed in 1954. Note + the relatively small growth increments in 1952 and 1953. + The growth-zone for 1955 (date of capture, May 8) is not + yet visible. This specimen grew more in the season of + hatching (1946) than the specimen shown above in Fig. 1. + _Right_--Interpectoral seam (A-- 3) of adult male showing + slowness of growth in later life. The widest growth-zone + seen here was formed in the tenth year and is followed by + four zones too narrow to measure accurately. It is uncertain + whether this specimen was still growing in the year it was + captured (1923). + + + [Illustration: PLATE 23] + + Ontogenetic change in color and markings of carapace. Radial + markings begin to develop at the onset of epidermal growth. + Markings are sharply defined in juveniles and young adults but + may be obscured in later life by the encroachment of dark + ground color or by wear on the shell. + Figures are as follows: + _Upper left_--Hatchling (A-- 1A1/2); + _Upper right_--Juvenile (A-- 1), one year old; + _Lower left_--Juvenile (A-- 1), one year old; + _Lower left_--Female (A-- 7/16) showing typical adult markings; + _Lower right_--Adult male (A-- A1/2showing blotched pattern + resulting from wear on shell. + + + [Illustration: PLATE 24] + + Ontogenetic change in color and markings of plastron. Dark + markings on plastra of hatchlings are unbroken. Dark radiations + appear when epidermal growth begins. + Figures are as follows: + _Upper left_--Hatchling (A-- 1A1/2); + _Upper right_--Juvenile (A-- 1); + _Lower left_--Female (A-- 7/16) showing typical adult markings; + _Lower right_--Adult male (A-- A1/2) showing the effect of wear + on markings. Plastra of old individuals are sometimes solid + yellow. Note the break in the plastron that has healed and + filled with ligamentous tissue. + + + [Illustration: PLATE 25] + + Ontogenetic change and sexual dimorphism in shape, color, and + markings of head and neck. Females retain much of the juvenal + pattern of spots and blotches. In males, the top and sides of + the head become greenish or bluish and markings are obscured. + FIGS. 1 and 3. Lateral and dorsal views of hatchling (A-- 3A1/2); + FIGS. 2 and 4. Lateral and dorsal views of juvenile (A-- 2); + FIGS. 5 and 6. Adult female (A-- 1); + FIGS. 7 and 8. Adult male (A-- 1) showing relatively wider and more + truncated snout in this sex. + + + [Illustration: PLATE 26] + + FIG. 1. A foraging station next to a rock fence at the Damm + Farm (June 28, 1958). The box turtle in foreground was in the + act of tearing apart a pile of partially dried cow dung to + obtain dung insects. + + FIG. 2. A depression (A-- A1/2) made by a foraging box turtle in a + pile of partially dried cow dung (June 28, 1958). Similar + "sign" of box turtles was found in cow dung everywhere on the + pasture at the Damm Farm. + + + [Illustration: PLATE 27] + + FIG. 1. Thread-laying device ("trailer") taped to the carapace + of an adult female _T. o. ornata_. The squares of tape on the + sides are to keep the bent-over ends of the wire axle from + catching on vegetation (A-- A1/2). + + FIG. 2. A dermal pocket ("cyst") removed from an adult + _T. ornata_ and cut open to show two larval bot flies + (_Sarcophaga cistudinis_) (A-- 2, May 15, 1956). + + + [Illustration: PLATE 28] + + FIGS. 1-3. Stages in courtship of _T. o. ornata_: male pursuing + female and biting her shell; male lunging at female in attempt + to mount; and, male just after mounting female (A-- A1/4). + FIG. 4. _T. o. ornata_ smelling food (A-- 1). + FIG. 5. _T. o. ornata_ in attitude of alertness after detecting + intruder (A-- 3/8). + FIG. 6. Tracks of _T. o. ornata_ in muddy ravine (A-- 1/8) (June 5, + 1956). + + + [Illustration: PLATE 29] + + FIG. 1. A small, nearly-healed, injury on the carapace of an + adult _T. o. ornata_ (A-- 2). Note regenerated epidermis at + bottom of depression and two pieces of dead bone ("splinter + scars") at upper right margin of depression. + FIG. 2. Injured area on the carapace of a juvenal _T. o. ornata_ + (A-- 3) with dead bone removed and laid to the right, exposing + regenerating epidermis in its early stages. + FIG. 3. Anterior edge of carapace (held away with forceps) of + specimen of _T. carolina_ (KU 51461, Gulf Co., Florida) that + had been badly burned (A-- 8/9). Nearly all the scutes of the + shell had fallen off and large pieces of dead bone could be + pulled away, exposing a gnarled mass of regenerating bone and + epidermis. + FIG. 4. A fracture that has healed and joined the tibia (upper bone) + to the fibula in a specimen of _T. o. ornata_ (KU 1877, A-- 3A1/2). + + + [Illustration: PLATE 30] + + _Top_: A shell of _T. o. ornata_ (A-- A1/2) as it was found at the + Damm Farm June 1, 1956. A serious injury (probably resulting + from burns) had exposed a large area of dead bone on the + carapace. + _Center_: Same shell with some of scutes removed. + _Bottom_: Same shell with dead bone removed to expose + regenerating epidermis and bone. Note that the injury involved + several of the neural bones; the turtle probably died as a + result of this injury but not before regeneration was + approximately one-half completed. + + +_Terrapene ornata_ seems to concentrate its breeding season (laying, +incubation, and hatching of eggs) more nearly in the middle of the +warm season than does _T. c. carolina_. This concentration probably is +an adaptation for breeding in open habitats where, under environmental +temperatures less equable than in forest, eggs would develop more +rapidly and hatch sooner but would be less able to survive winter +temperatures. + +Males of _T. o. ornata_ become sexually mature when younger and +smaller than females and rarely grow as large as females. Nichols +(1939a:20) indicated the reverse to be true of _T. c. carolina_; +Nichols further indicated that growth continued some six to eight +years after puberty. Most individuals of _T. o. ornata_ attain maximum +size within two to three years after puberty. + +Although it is difficult to be certain about the adaptive value of +color and pattern, it seems that in box turtles, as in many other +kinds of animals, patterns and colors most nearly blending with those +of the habitat have some selective value in providing concealment from +enemies. The pattern of linear radiations in _T. o. ornata_ closely +resembles the patterns formed by light passing through grasses and +associated vegetation and camouflages the turtle. In a similar manner, +partial or complete loss of radial markings in _T. o. luteola_ seems +to provide concealment in habitats where vegetation is sparse and +where blending with the substrate is of survival value. The patterns +of blotches and broken radiations in most of the subspecies of _T. +carolina_ likewise provide camouflage by tending to match patterns +formed by the light passing through a leafy canopy. + +Although ornate box turtles are omnivorous, they probably depend on +insects as a dietary staple. In years when preferred kinds of insects +were unusually abundant, the turtles grew more than in other years. A +large proportion of the insects eaten is obtained by foraging in or +near dung. Alteration of the dung community--at least in a physical +sense, but presumably also by influencing the successional stages of +the dung biota--is one of the few evident effects of box turtles on +the environment. Although certain kinosternids (Carr, 1952:93), emyids +(Deraniyagala, 1939:257; Loveridge and Williams, 1957:198), and +testudinids (Loveridge and Williams, _op. cit._:247) eat mammalian +feces, _T. ornata_ is seemingly the only chelonian that habitually +seeks its staple diet in dung. The habit seems to be yet another +specialization for terrestrial existence. The carnivorous habits of +_T. ornata_ reverse the general trend toward omnivorous and +herbivorous habits in other turtles that have become partly (emyids) +or wholly (testudinids) terrestrial. + +It seems remarkable that none of the species of true tortoises +occurring in the grasslands of the world has developed insectivorous +habits or utilized the unique food niche (in regard to dung-foraging) +filled by ornate box turtles in the Great Plains; tortoises are, as +far as is known, strictly herbivorous. The ranges of _Gopherus_ and +_Terrapene_ are now almost mutually exclusive and the two kinds do not +compete with each other for food in the few places where they occur +together. It is known, however, that box turtles (_T. longinsulae_, +_ornata_-like, earliest known box turtle) and true tortoises (genera +_Testudo_ and _Gopherus_, see Williams, 1950:25-26, Fig. 2) occurred +together in what is now the Great Plains in early Pliocene times and +probably for some time before and after this. Assuming that food +habits of fossil representatives of these genera were somewhat like +the habits of recent representatives, ornate box turtles may have +developed insectivorous habits at a time when other food niches were +filled by herbivorous tortoises. Box turtles possibly survived +subsequent changes in habitat that made it impossible for populations +of large tortoises to exist in the Great Plains. + + + + +SUMMARY + + +Box turtles of the genus _Terrapene_ are emyid turtles that are +specialized for terrestrial existence. Two of the seven species now +recognized--_T. ornata_ and _T. carolina_--occur in the United States. +_Terrapene carolina_ inhabits forested areas in the east whereas _T. +ornata_ is characteristic of open grassy areas in the west; the ranges +of the two species overlap in the broad belt of prairie-forest ecotone +in the central United States. _Terrapene ornata_ is considered to be +the most specialized of living box turtles. + +The natural history of _T. o. ornata_ Agassiz was studied in the +period, 1953 to 1957. Intensive field studies were made in Douglas +County, northeastern Kansas, on a small area of prairie and on the +University of Kansas Natural History Reservation. Field observations +were made also in a number of other places in eastern Kansas. +Laboratory studies supplemented field studies. + +Habitats occupied are chiefly open areas; they vary in regard to food +supply, temperature, moisture, and kind of soil. The grassy prairies +of Nebraska, Kansas, Oklahoma, and northern Texas seem to provide +optimum habitat for ornate box turtles; in these areas box turtles are +active on a majority of days from April to October. The subspecies +_luteola_ is adapted to the more rigorous and arid environment of the +southwestern United States, where activity may be possible for only a +few weeks in the year. The remainder of the year is spent in a state +of quiescence. Factors limiting the distribution of _T. ornata_ are: +1) the presence of a substrate too hard to permit digging of nests and +forms (altitudinal distribution in southwestern United States and +distribution at western edge of the range); 2) temperatures causing +the ground to freeze deep enough (approximately 30 inches) to kill +turtles in hibernacula (northern edge of range); and, 3) the lack of +one or more relatively wet periods in the course of the warm season, +preventing at least temporary emergence from quiescence (southwestern +part of range). The activities of man probably have affected +population density in local areas but limit the geographic range only +in the north (Blanchard, 1923:19-20, 24) where intensive cultivation +probably has excluded the species. + +Preferred habitat in northeastern Kansas is open rolling grassland +grazed by cattle; populations are most dense near natural breaks in +the grassy vegetation such as fences, scattered rocks on hillsides, +ravines, and stream-beds. + +Mating occurs most commonly in spring and autumn; courtship behavior +includes pushing and biting on the part of the male. In coitus the +hind legs of the male are held tightly by the female; the male falls +backward after coitus, still clasped by the female. A few sperm are +stored in the oviducts; fertilization without reinsemination can +occur. The spermatogenic cycle begins in May and reaches its peak in +September, when large numbers of sperm and spermatids are present in +the testes; the cycle is completed in October, when sperm pass into +the epididymides. The testes are smallest in spring and largest in +September. Females are inseminated with sperm produced in the +preceding year. The ovarian cycle begins in midsummer, soon after +ovulation, and continues up to the time of the next ovulation. +Follicular growth is rapid in the period from spring emergence to +ovulation. Large follicles remaining after ovulation represent, in +many instances, eggs that will be laid later in the same season. +Follicular atresia is never great enough to account for the +destruction of all large follicles remaining after ovulation. All +mature females lay at least one clutch of eggs per year. It is +estimated that one-third of the females produces two clutches of eggs +in a single season. Second clutches contain fewer eggs than first +clutches. An alternation of ovarian activity occurs, whereby one ovary +is more active than its partner in one season and less active in the +next season. Alternating activity of ovaries accounts in part for the +reduced number of eggs in young females, breeding for the first time, +and in older, nearly senile females. Extrauterine migration of ova +results usually in a more even distribution of eggs in the oviducts. +Corpora lutea constitute an accurate record of the number of eggs +produced by the ovary as well as the number of eggs laid. + +Nesting occurs from May through July but is most common in mid-June; +some of the females nesting early in the season lay a second clutch of +eggs in July. Nests are dug in the earth by the female using her hind +legs. Preferred nesting sites are open, well-drained places with a +soft substrate. The nesting site is selected after a period of +wandering, in which the female tests the substrate at a number of +places; some females search for a nest site for more than a week. Nest +digging begins in the evening and is usually completed after dark. +Captive females dug a preliminary cavity in which the body rested +during the digging of the main nest cavity. The entire clutch of eggs +is laid in one nest. The average number of eggs in 23 clutches was 4.7 +(range, 2 to 8). The average size of eggs tends to be inversely +proportional to the number of eggs in a clutch. Eggs increase in bulk +by absorption of water in the course of incubation. Immersion in water +for short periods does not harm eggs. The incubation period under +favorable environmental conditions is approximately 65 days; cool, +damp conditions prolong the incubation period and probably constitute +an important factor of prenatal mortality in certain years. Eggs that +do not hatch before winter probably do not survive. Emergence of +hatchlings from the nest may, however, be delayed until spring if the +soil is dry in autumn. Hatchlings can probably escape freezing by +burrowing into the walls of the nest. Infertility and prenatal +mortality account for at least 40 per cent of the eggs laid, according +to laboratory findings. Progeny of a single adult female (considering +factors of mortality, multiple layings, and average age of puberty) +would number approximately 300 after 20 years. Reproductive processes +probably continue throughout life, although possibly at a somewhat +reduced rate in later life. + +Young box turtles are active soon after hatching but become quiescent +if allowed to burrow in soil or if they are covered with damp cotton. +Some captive hatchlings take live food in the first days of life but +others do not eat until the following spring; initiation of growth is +coincident with initiation of regular feeding. The yolk sac retracts +mainly during hatching; it sometimes ruptures after hatching. The +caruncle remains on the beak for a variable length of time, but never +is present in the spring following hatching. + +Major growth-rings on the epidermal laminae are formed regularly, one +after each season of growth, in the first 10 to 14 years of life. +Minor growth-rings occur between major rings and are shallower. Growth +of epidermal laminae results from the formation, in spring, of a new +layer of epidermis beneath the existing scute. The peripheral +projection of the new layer is distinct in texture and color from the +older part of the scute and is separated from it by a major +growth-ring. Minor growth-rings form when growth slows or temporarily +stops during periods of quiescence; no new layer of epidermis is +formed. Growth-rings constitute an accurate record of growth that can +be studied at any time in the life of the turtle; they are accurate +indicators of age only as long as regular annual growth persists. + +Growth in the season of hatching depends on early hatching and early +emergence from the nest. Turtles that remain in the nest until spring +probably do not grow. Slightly less than half of the free-living +individuals studied grew in the season of hatching. Precociousness in +early life often results in the attainment of sexual maturity at an +earlier than average age. + +Growth is rapid at first (increments in plastral length average 68, +29, and 18 per cent, respectively, in the first three years) and then +slows gradually until puberty. Attainment of sexual maturity is more +closely correlated with size than with age. Males mature when smaller +(76 per cent were mature when plastron 100 to 109 mm. long) and +younger (average age, eight to nine years) than females (66 per cent +were mature when plastron 110 to 119 mm. long, average age at +maturity, ten to eleven years) but females grow larger than males. A +few individuals of each sex reach puberty three to four years sooner +than average. + +The average number of growing days per season is approximately 160. +Amount of growth in any season depends on climatic factors that +influence food supply and foraging conditions. Growth rate is directly +correlated with precipitation, being highest when large populations of +grasshoppers and long periods of favorable weather occur in the same +year. Zones of epidermis formed in years when growth was especially +slow or especially fast constituted landmarks that were helpful in +interpreting growth-histories. Growth stops two to three years after +puberty. The total growing period is estimated to be not more than 15 +to 20 years. Longevity is estimated to be approximately 50 years. + +A number of changes in structure and appearance occur in the period +from hatching to puberty. Fontanelles of the bony shell close at or +before puberty. Movable parts of the plastron are not functional until +the fourth year. Markings on the carapace change from a series of dots +to distinct, straight-sided radiations, and a similar pattern develops +on the plastron. Markings on the heads of females resemble those of +juveniles but males have greenish heads. Males further differ from +females in having a red iris, more brightly colored antebrachial +scales, and a turned in first toe. + +Analysis of some 500 body temperatures (Centigrade) obtained under +natural conditions revealed the following: the optimum temperature for +activity is near 30 degrees; box turtles emerge from cover usually +when body temperature is 24 degrees or higher, and almost never when +the body temperature is below 15 degrees; body temperature is raised +to optimum by basking in open areas although activity begins at +suboptimum temperatures if basking is impossible; cover of dens, +burrows, or forms is sought when the body temperature rises above 30 +degrees; and, maximum and minimum body temperatures that would be +lethal to box turtles (for prolonged periods) are approximately 40 and +zero degrees, respectively. Laboratory experiments showed speed of +response to environmental temperature to be inversely proportional to +bulk; hatchlings could be chilled or warmed more than twice as fast as +adults and were active within a narrower range of temperature. Ornate +box turtles in general are subject to a narrower range of thermal +activity than are aquatic turtles that occur in the same areas. + +Box turtles are dormant approximately five and one-half months of the +year--from late October to mid-April. Warm weather in November and +late March sometimes stimulates temporary activity but dormancy is +uninterrupted from mid-November to early March. Forms, dens, and +burrows are used as hibernacula. Depth of hibernacula is dependent on +severity of temperatures and amount of vegetational cover; hibernacula +in open grassland were seven to 18 inches deep whereas those in wooded +areas were six inches or shallower. Box turtles are ordinarily +solitary when hibernating. Injuries and deaths due to freezing +probably occur in the coldest part of the winter. The lowest body +temperature of a turtle that survived a winter was 2.7 degrees; an +individual, the temperature of which was nearly zero for several days, +subsequently died. Turtles burrow upward at the end of hibernation and +remain just below the surface for a week or two before emerging. The +primary stimulus for emergence seems to be a period of warm moist +weather. + +Populations of _T. ornata_ observed under natural conditions were +chiefly carnivorous, although captives ate a variety of animal and +vegetable matter. Insects, consisting chiefly of beetles, +caterpillars, and one species of grasshopper, comprised approximately +89 per cent (by volume) of the food present in stomachs. Beetles +(chiefly scarabaeids and carabids) are obtained in or near dung and +seem to constitute the most important staple element of the diet. +Piles of dung, disturbed by turtles in the course of their foragings, +were characteristic "sign" of _T. ornata_ in the areas studied. + +Insects form the bulk of the diet for most of the year, although +certain other foods, when especially abundant for short periods +(mulberries for example), are eaten in large quantity or eaten to the +exclusion of all other foods. Ornate box turtles occasionally eat the +eggs and young of ground-nesting birds and slightly damage vegetables, +but in no instance do these feeding habits significantly affect the +economy of man. Box turtles probably benefit man by destroying large +numbers of crop-damaging insects (locustids and noctuid caterpillars). + +Box turtles were more numerous than most kinds of reptiles at the Damm +Farm and were the most conspicuous of any kind of reptile. One hundred +and ninety-four turtles were marked; one-fourth of these were +recaptured at least twice. Population density in certain areas of +favorable habitat ranged from 2.6 to 6.3 turtles per acre. The total +number of individuals on the study area was estimated to be 286. The +marked population consisted of 53 per cent adult or subadult females, +31 per cent adult males, and 16 per cent juveniles of undetermined +sex. Only six individuals had plastra shorter than 60 millimeters. +Small box turtles are not so rare as these samples indicate; they are +infrequently obtained because their smallness and ability to blend +with the substrate make them difficult to see. More females than males +were found in all months of the season of activity, excepting April +and August when more males were found; the preponderance of females +was greatest in the nesting season (June and July). + +Ornate box turtles walk with the shell held off the substrate. They +are able to climb steep embankments or low barriers with some +facility. Swimming ability is sufficient to permit survival in water +and traversal of water-barriers but ornate box turtles almost never +swim voluntarily. + +Daily activity consists of periods of basking, foraging, and rest, the +durations of which are influenced by temperature and humidity. There +is no activity after dark except that of nesting females. After +several days of activity there is a period of rest; rest periods +seemed not to be correlated with climatic conditions. The average +distance traveled per day in summer is 200 to 300 feet. Movements of +gravid females are more extensive (average, 363 feet per day) than +those of other members of the population; one individual traveled +approximately one-fourth of a mile in a single day. Turtles removed +from their normal home ranges traveled farther per day than any other +group. Movements in autumn are less extensive (average, 152 feet per +day) than at other times in the season of activity. + +Individual box turtles tended to remain in small areas for long +periods; these areas were interpreted as home ranges. The estimated +average radius of 44 home ranges was 278 feet (average area, 5.6 +acres). The average area of eight home ranges that were actually +measured was five acres. General suitability of habitat and certain +physical features of terrain (rock fences, ravines, barren fields) +that acted as barriers were thought to be the most important factors +governing size of home range. Of two turtles removed more than +one-fourth of a mile from their home ranges, one homed and one did +not. Home ranges of turtles of all ages and sexes overlap broadly. +There was no indication that territoriality or social hierarchy +existed in the population studied. + +Box turtles are subject to injury from natural causes that include +fire, cold, molestation by predators, and trampling by cattle. +Automobiles and farm machinery now constitute major causes of +mortality and serious injury. Capacity to recover after serious injury +is great but there is increased chance for secondary injury, +infection, and predation in the period of recovery. Pits on the shell +from unknown causes ("shell pitting") are less common in ornate box +turtles than in other kinds of turtles. + +Ectoparasites infesting _T. ornata_ are larvae of chigger mites (genus +_Trombicula_) and larvae of bot flies (_Sarcophaga cistudinis_). +Ectoparasites usually have little adverse effect on the turtles, +although heavy infestations cause occasional injury or death. + +Few natural enemies other than man are known; however most wild +carnivores as well as opossums, large birds, and domestic dogs and +cats are suspect as predators. The incidence of predation on eggs and +small juveniles is far greater than on older juveniles and adults. +Adults of _T. ornata_ occasionally attack smaller individuals. + +Ornate box turtles are able to detect the presence of intruders, by +sight, from a distance of several hundred feet in open country; +apparently, intruders are not detected until seen. Defensive behavior +is passive; the shell is closed tightly in response to painful stimuli +and, in some instances, at the sight of an intruder. Juveniles usually +void odoriferous fluid from the musk glands when handled but adults do +so only in response to pain or injury. The function of the musk glands +is unknown; possibly the odor of musk is a means of sexual +identification or stimulation. Although the musk is probably +distasteful to predators, repellent odor alone seems to be of doubtful +value as a defense mechanism. + + + + +LITERATURE CITED + + + AGASSIZ, L. + 1857. Embryology of the turtle. Contributions to the natural + history of the United States, 2(3):451-643, 27 pls., + 12 wood-cuts in text, tables. Little, Brown and Co., + Boston. + + ALLARD, H. A. + 1935. The natural history of the box turtle. Sci. Monthly, + 41:325-338. + 1939. Mating of the box-turtle ending in death of the male. + Copeia, 1939(2):109. + + ALTLAND, P. D. + 1951. Observations on the structure of the reproductive organs of + the box turtle. Journ. Morph., 89:599-621, 16 figs. + + AUFFENBERG, W. + 1958. Fossil turtles of the genus _Terrapene_ in Florida. + Bull. Florida State Mus., Biol. Sci., 3(2):53-92, 15 figs., + 5 tables. + + BAILEY, R. M. + 1948. Winter mortality in the snake _Storeria dekayi_. Copeia, + 1948 (3):215. + + BELDING, D. L. + 1952. Textbook of clinical parasitology. Appleton-Century-Crofts, + Inc., New York, viii + 1139 pp., 283 figs. + + BLANCHARD, F. N. + 1923. The amphibians and reptiles of Dickinson County, Iowa. Univ. + Iowa, Studies Nat. Hist., 10:19-26. + + BOGERT, C. M. + 1937. Note on the growth rate of the desert tortoise, _Gopherus + agassizi_. Copeia, 1937(3):191-192. + + BOOTH, K. + 1958. Development of eggs and young of desert tortoise. + Herpetologica, 13(4):261-263. + + BREDER, R. B. + 1927. Turtle trailing: a new technique for studying the life habits + of certain Testudinata. Zoologica, 9(4):231-243. + + BRENNAN, L. A. + 1937. A study of the habitat of the reptiles and amphibians of + Ellis County, Kansas. Trans. Kansas Acad. Sci., 40:341-347, + 1 table. + + BRUMWELL, M. J. + 1940. Notes on the courtship of the turtle, _Terrapene ornata_. + Trans. Kansas Acad. Sci., 43:391-392. + + CAGLE, F. R. + 1939. A system of marking turtles for future identification. + Copeia, 1939(3):170-173, 5 figs. + 1944. Home range, homing behavior, and migration in turtles. Misc. + Publ., Mus. Zool., Univ. Michigan, No. 61, 34 pp., 2 pls., + 4 figs., 5 tables. + 1945. Recovery from serious injury in the painted turtle. Copeia, + 1945(1):45. + 1946. The growth of the slider turtle, _Pseudemys scripta elegans_. + Amer. Midl. Nat., 36(3):685-729, 8 figs., 3 pls., 13 tables. + 1948. The growth of turtles in Lake Glendale, Illinois. Copeia, + 1948(3):197-203. + 1950. The life history of the slider turtle, _Pseudemys scripta + troostii_ (Holbrook). Ecol. Monogr., 20(l):31-54, 18 figs., + 4 tables. + 1954. Observations on the life cycles of painted turtles (genus + _Chrysemys_). Amer. Midl. Nat., 52(l):225-235, 2 figs., + 1 table. + + CAGLE, F. R., and TIHEN, J. + 1948. Retention of eggs by the turtle _Deirochelys reticularia_. + Copeia, 1948(1):66. + + CAHN, A. R. + 1937. The turtles of Illinois. Illinois Biol. Monogr., + 16(1-2):1-218, 31 pls., 15 figs., 20 maps, 20 tables. + + CAHN, A. R., and CONDER, E. + 1932. Mating of the box turtles. Copeia, 1932(2):86-88, 2 figs. + + CARPENTER, C. C. + 1956. Carapace pits in the three-toed box turtle, _Terrapene + carolina triunguis_ (Chelonia-Emydidae). Southwestern + Naturalist, 1(2):83-86, 1 fig., 1 table. + + CARPENTER, J. R. + 1940. The grassland biome. Ecol. Monogr., 10(4):617-684, 7 figs., + 7 tables. + + CARR, A. + 1952. Handbook of-turtles: the turtles of the United States, Canada, + and Baja California. Cornell Univ. Press, xv + 542 pp., + 37 figs., 82 pis., 15 tables, 23 maps. + + CLARKE, R. F. + 1950. Notes on the ornate box turtle. Herpetologica, 6(2):54. + 1958. An ecological study of reptiles and amphibians in Osage + County, Kansas. Emporia St. Res. Stud., 7(1):52 pp., + 15 figs., 4 tables. + + COWLES, R. B., and BOGERT, C. M. + 1944. A preliminary study of the thermal requirements of desert + reptiles. Bull. Amer. Mus. Nat. Hist., 83(5):261-296, + figs. 1-3, pls. 19-29, 1 table. + + CUNNINGHAM, B. + 1939. Effect of temperature upon the developmental rate of the + embryo of the diamond back terrapin (_Malaclemys centrata_ + Lat). Amer. Nat., 73:381-384. + + DANINI, E. S. + 1946. Histological processes as observed in the regeneration of + the carapace of the tortoise _Emys orbicularis_ L. Bull. + Acad. Sci. U. S. S. R., Biol., 5:581-594. + + DERANIYAGALA, P. E. P. + 1939. The tetrapod reptiles of Ceylon. Vol. 1, Testudinates and + Crocodilians. Columbo, ix-xxii + 412 pp., 137 figs., + 24 pls., 62 tables. + + DITMARS, R. L. + 1934. A review of the box turtles. Zoologica, 17(1):1-44, 41 figs. + + DRIVER, E. C. + 1946. Delayed hatching in the box turtle. Copeia, 1946(3):173-174. + + EVANS, L. T. + 1952. Endocrine relationships in turtles III. Some effects of male + hormone in turtles. Herpetologica, 8(2):11-14. + 1953. The courtship pattern of the box turtle, _Terrapene c. + carolina_. Herpetologica, 9(4):189-192, 6 figs. + 1954. Courtship and territorial behavior of lower vertebrates (A + review). Mimeographed, 50 pp. + + EWING, H. E. + 1939. Growth in the eastern box-turtle with special reference to + the dermal shields of the carapace. Copeia, 1939(2):87-92, + 3 figs. + 1943. Continued fertility in female box turtles following mating. + Copeia, 1943(2):112-114. + + FINNERAN, L. C. + 1948. Reptiles at Branford, Connecticut. Herpetologica, + 4(4):123-126. + + FITCH, H. S. + 1952. The University of Kansas Natural History Reservation. Univ. + Kansas Mus. Nat. Hist., Misc. Publ., No. 4, 38 pp., 4 pls., + 3 figs. + 1954. Life history and ecology of the five-lined skink, _Eumeces + fasciatus_. Univ. Kansas Publ., Mus. Nat. Hist., + 8(1):1-156, 2 pls., 26 figs, in text, 17 tables. + 1955. Habits and adaptations of the Great Plains skink (_Eumeces + obsoletus_). Ecol. Monogr., 25:59-83, 11 figs., 10 tables. + 1956a. An ecological study of the collared lizard (_Crotaphytus + collaris_). Univ. Kansas Publ., Mus. Nat. Hist., + 8(3):213-274, pls. 3-6, figs. 1-10, 9 tables. + 1956b. Temperature responses in free-living amphibians and reptiles + of northeastern Kansas. Univ. Kansas Publ., Mus. Nat. + Hist., 8(7):417-476, 10 figs. in text, 6 tables. + 1958. Home ranges, territories, and seasonal movements of + vertebrates of the University of Kansas Natural History + Reservation. Univ. Kansas Publ., Mus. Nat. Hist., + 11(3):63-326, 6 pls., 24 figs., 3 tables. + + FORBES, T. R. + 1940. A note on reptilian sex ratios. Copeia, 1940(2):132. + + FOX, W. + 1952. Seasonal variation in the male reproductive systems of + Pacific Coast garter snakes. Journ. Morph., 90(3):481-553, + 5 pls., 13 figs., 3 tables. + 1956. Seminal receptacles of snakes. Anat. Rec., 124(3):519-540, + 3 pls., 1 table. + + GEHLBACH, F. R. + 1956. Annotated records of southwestern amphibians and reptiles. + Trans. Kansas Acad. Sci., 59(3):364-372. + + GOULD, E. + 1957. Orientation in box turtles, _Terrapene c. carolina_ + (Linnaeus). Biol. Bull., 112(3):336-348, 5 figs. + + GRANT, C. + 1936. The southwestern desert tortoise _Gopherus agassizii_. + Zoologica, 21:225-229. + + HAY, O. P. + 1908a. Description of five species of North American fossil turtles, + four of which are new. Proc. U. S. Nat. Mus., + 35(1640):161-169, pls. 26-27, 3 figs. + + 1908b. The fossil turtles of North America. Carnegie Inst. + Washington, Publ. no. 75, iii-iv + 568 pp., 113 pls., + 704 figs. + + HILDEBRAND, S. F., and PRYTHERCH, H. F. + 1947. Diamond-back terrapin culture. U. S. Dept. Int., Fishery + leaflet no. 216, 3 pp., mimeographed. + + HOFFMANN, C. K. + 1890. Klassen und Ordnungen des Thier-Reichs. Bd. 6, Ab. 3, + Reptilien. I. SchildkrA¶ten. Winter, Leipzig, 442 pp., + 48 pls., 1 woodcut. + + HUNT, T. J. + 1957. Notes on diseases and mortality in Testudines. Herpetologica, + 13(1):19-23, 1 table. + + LATHAM, R. + 1917. Studying the box turtle. Copeia, 1917(39):15-16. + + LEGLER, J. M. + 1954. Nesting habits of the western painted turtle, _Chrysemys + picta bellii_ (Gray). Herpetologica, 10(3):137-144. + 1956. A simple and practical method of artificially incubating + reptile eggs. Herpetologica, 12(4):290. + 1958. Extra-uterine migration of ova in turtles. Herpetologica, + 14(1):49-52, 1 fig. + + LEGLER, J. M., and FITCH, H. S. + 1957. Observations on hibernation and nests of the collared lizard, + _Crotaphytus collaris_. Copeia, 1957(4):305-307, 1 pl. + + LEWIS, T. H. + 1950. The herpetofauna of the Tularosa Basin and Organ Mountains + of New Mexico with notes on some ecological features of + the Chihuahuan desert. Herpetologica, 6(1):1-10, 8 figs. + + LINCOLN, F. C. + 1930. Calculating waterfowl abundance on the basis of banding + returns. U. S. Dept. Agri., Circ. 118, 4 pp., 1 fig., + 2 tables. + + LOOMIS, R. B. + 1956. The chigger mites of Kansas (Acarina, Trombiculidae). Univ. + Kansas Sci. Bull., 37, pt. II, no. 19:1195-1443, 49 figs., + 29 maps, 3 tables. + + LOVERIDGE, A., and WILLIAMS, E. + 1957. Revision of the African tortoises and turtles of the suborder + Cryptodira. Bull. Mus. Comp. Zool., 115(6):165-557, 18 pls., + 62 figs., 10 tables. + + LYNN, W. G., and ULLRICH, M. C. + 1950. Experimental production of shell abnormalities in turtles. + Copeia, 1950(4):253-262, 2 pls., 2 figs. + + MARR, J. C. + 1944. Notes on amphibians and reptiles from the central United + States. Amer. Midl. Nat., 32(2):478-490, 1 table. + + MATTOX, N. T. + 1936. Annular rings in the long bones of turtles and their + correlation with size. Trans. Illinois State Acad. Sci., + 28:225-226. + + MEDSGER, O. P. + 1919. Notes on the first turtle I ever saw. (Abstract of a paper + presented Nov. 15, 1918) Copeia, 1919(69):29. + + MCMULLEN, D. B. + 1940. Cutaneous myiasis in a box turtle. Proc. Oklahoma Acad. Sci., + 20:23-25, 2 figs. + + MILLER, L. + 1955. Further observations on the desert tortoise, _Gopherus + agassizi_, of California. Copeia, 1955(2):113-118, 1 pl., + 2 figs., 2 tables. + + MILLER, M. R. + 1948. The seasonal histological changes occurring in the ovary, + corpus luteum, and testis of the viviparous lizard, + _Xantusia vigilis_. Univ. California Publ. Zool., + 47:197-224. + + MITSUKURI, K. + 1895. How many times does the snapping turtle lay eggs in one + season? Zool. Mag. Tokyo, 7 (85):143-147. + + NEILL, W. T. + 1948a. Hibernation habits of amphibians and reptiles in Richmond + County, Georgia. Herpetologica, 4(3):107-114. + 1948b. Odor of young box turtles. Copeia, 1948(2):130. + + NICHOLS, J. T. + 1939a. Data on size, growth and age in the box turtle, _Terrapene + carolina_. Copeia, 1939(1):14-20, 2 figs., 2 tables. + 1939b. Range and homing of individual box turtles. Copeia, + 1939(3):125-127. + + NORRIS, K. S., and ZWEIFEL, R. G. + 1950. Observations on the habits of the ornate box turtle, + _Terrapene ornata_ (Agassiz). Nat. Hist. Misc., no. 58, + 4 pp. + + ODUM, E. P., and KUENZLER, E. J. + 1955. Measurement of territory and home range size in birds. Auk, + 72(2):128-137, 3 figs., 2 tables. + + OLIVER, J. A. + 1955. The natural history of North American amphibians and reptiles. + Van Nostrand, xi + 359 pp., 74 figs., 14 tables. + + ORTENBURGER, A. I., and FREEMAN, B. + 1930. Notes on some reptiles and amphibians from western Oklahoma. + Publ. Univ. Oklahoma Biol. Surv., 2(4):175-188, 2 maps. + + PACKARD, R. L. + 1956. The tree squirrels of Kansas. Univ. Kansas Mus. Nat. Hist., + Misc. Publ., no. 11, 67 pp., 2 pls., 10 figs. + + PENN, G. H., JR., and POTTHARST, K. E. + 1940. The reproduction and dormancy of _Terrapene major_ in New + Orleans. Herpetologica, 2(2):25-29. + + PETERS, J. A. + 1948. The box turtle as a host for dipterous parasites. Amer. Midl. + Nat., 40(2):472-474. + + RAINEY, D. G. + 1953. Death of an ornate box turtle parasitized by dipterous larvae. + Herpetologica, 9(2):109. + + RISLEY, P. L. + 1933. Observations on the natural history of the common musk turtle, + _Sternotherus odoratus_ (Latreille). Pap. Michigan Acad. + Sci., Arts and Letters, 17:685-711, figs. 78-79, 1 table. + 1938. Seasonal changes in the testis of the musk turtle, + _Sternotherus odoratus_ L. Journ. Morph., 63(2):301-317, + 2 pls., 1 fig. + + RODECK, H. G. + 1949. Notes on box turtles in Colorado. Copeia, 1949(1):32-34. + + ROKOSKY, E. J. + 1948. A bot-fly parasitic in box turtles. Nat. Hist. Misc., no. 32, + 2 pp. + + SCHNECK, J. + 1886. Longevity of turtles. Amer. Nat., 20(9):897. + + SERGEEV, A. + 1937. Some materials to the problem of the reptilian post-embryonic + growth. Zool. Journ. Moscow, 16:723-735. + 1939. The body temperature of reptiles in natural surroundings. + Comptes Rendus (Doklady) de l'Acad. des Sci. de l'USSR, + 22:49-52. + + SMITH, H. M., and JAMES, L. F. + 1958. The taxonomic significance of cloacal bursae in turtles. + Trans. Kansas Acad. Sci., 61(1):86-96. + + SMITH, H. M., and RAMSEY, L. W. + 1952. A new turtle from Texas. Wasmann Journ. Biol., 10(1):45-54, + 1 pl., 1 table. + + SMITH, R. C. + 1954. An analysis of 100 years of grasshopper populations in Kansas + (1854-1954). Trans. Kansas Acad. Sci., 57(4):397-433, + 1 pl., 5 figs. + + STICKEL, L. F. + 1950. Populations and home range relationships of the box turtle, + _Terrapene c. carolina_. Ecol. Monogr., 20:351-378, + 15 figs., 5 tables. + + STOCK, C., and BODE, F. D. + 1936. The occurrence of flints and extinct animals in pluvial + deposits near Clovis, New Mexico. Part III,--Geology and + vertebrate paleontology of the late Quaternary near Clovis, + New Mexico. Acad. Nat. Sci. Philadelphia, 88:219-241, + pls. 5-10, 6 figs. in text. + + STRECKER, J. K., JR. + 1908. The reptiles and batrachians of McLennan County, Texas. Proc. + Biol. Soc. Washington, 21:69-84. + + SURFACE, H. A. + 1908. First report on the economic features of turtles of + Pennsylvania. Zool. Bull., Pennsylvania Dept. Agr., + 6(4-5):105-195, pls. 4-12, 16 figs., tables. + + TAYLOR, W. E. + 1895. The box tortoises of North America. Proc. U. S. Nat. Mus., + 17 (1019):573-588, 7 figs. + + WEVER, E. G., and VERNON, J. A. + 1956. Auditory responses in the common box turtle. Proc. Nat. Acad. + Sci., 42(12):962-965. + + WILLIAMS, E. + 1950. _Testudo cubensis_ and the evolution of western hemisphere + tortoises. Bull. Amer. Mus. Nat. Hist., 95(1):1-36, + pls. 1-8, 2 figs. + + WOODBURY, A. M., and HARDY, R. + 1948. Studies of the desert tortoise _Gopherus agassizii_. Ecol. + Monogr., 18:145-200, 25 figs., 4 tables. + + +_Transmitted August 27, 1959._ + + + + +PRINTED IN +THE STATE PRINTING PLANT +TOPEKA, KANSAS +1960 + +[Union Label] + +28-773 + + + + +UNIVERSITY OF KANSAS PUBLICATIONS + +MUSEUM OF NATURAL HISTORY + + +Institutional libraries interested in publications exchange may obtain +this series by addressing the Exchange Librarian, University of Kansas +Library, Lawrence, Kansas. Copies for individuals, persons working in +a particular field of study, may be obtained by addressing instead the +Museum or Natural History, University of Kansas, Lawrence, Kansas. +There is no provision for sale of this series by the University +Library, which meets institutional requests, or by the Museum of +Natural History, which meets the requests of individuals. When +individuals request copies from the Museum, 25 cents should be +included, for each separate number that is 100 pages or more in +length, for the purpose of defraying the costs of wrapping and +mailing. + + + * An asterisk designates those numbers of which the Museum's + supply (not the Library's supply) is exhausted. Numbers + published to date, in this series, are as follows: + + Vol. 1. Nos. 1-26 and index. Pp. 1-638, 1946-1950. + + *Vol. 2. (Complete) Mammals of Washington. By Walter W. Dalquest + Pp. 1-444, 140 figures in text. April 9, 1948. + + Vol. 3. *1. The avifauna of Micronesia, its origin, evolution, and + distribution. By Rollin H. Baker. Pp. 1-359, + 16 figures in text. June 12, 1951. + + *2. A quantitative study of the nocturnal migration of birds. + By George H. Lowery, Jr. Pp. 361-472, 47 figures in + text. June 29, 1951. + + 3. Phylogeny of the waxwings and allied birds. By M. Dale + Arvey. Pp. 473-530, 49 figures in text, 13 tables. + October 10, 1951. + + 4. Birds from the state of Veracruz, Mexico. By George H. + Lowery, Jr., and Walter W. Dalquest. Pp. 531-649, + 7 figures in text, 2 tables. October 10, 1951. + + Index. Pp. 651-681. + + *Vol. 4. (Complete) American weasels. By E. Raymond Hall. Pp. 1-466, + 41 plates, 31 figures in text. December 27, 1951. + + Vol. 5. Nos. 1-37 and index. Pp. 1-676, 1951-1953. + + *Vol. 6. (Complete) Mammals of Utah, _taxonomy and distribution_. + By Stephen D. Durrant. Pp. 1-549, 91 figures in text, + 30 tables. August 10, 1952. + + Vol. 7. *1. Mammals of Kansas. By E. Lendell Cockrum. Pp. 1-303, + 73 figures in text, 37 tables. August 25, 1952. + + 2. Ecology of the opossum on a natural area in northeastern + Kansas. By Henry S. Fitch and Lewis L. Sandidge. + Pp. 305-338, 5 figures in text. August 24, 1953. + + 3. The silky pocket mice (Perognathus flavus) of Mexico. + By Rollin H. Baker. Pp. 339-347, 1 figure in text. + February 15, 1954. + + 4. North American jumping mice (Genus Zapus). By Philip H. + Krutzsch. Pp. 349-472, 47 figures in text, 4 tables. + April 21, 1954. + + 5. Mammals from Southeastern Alaska. By Rollin H. Baker + and James S. Findley. Pp. 473-477. April 21, 1954. + + 6. Distribution of Some Nebraskan Mammals. By J. Knox + Jones, Jr. Pp. 479-487. April 21, 1954. + + 7. Subspeciation in the montane meadow mouse, Microtus + montanus, in Wyoming and Colorado. By Sydney Anderson. + Pp. 489-506, 2 figures in text. July 23, 1954. + + 8. A new subspecies of bat (Myotis velifer) from + southeastern California and Arizona. By Terry A. + Vaughan. Pp. 507-512. July 23, 1954. + + 9. Mammals of the San Gabriel mountains of California. + By Terry A. Vaughan. Pp. 513-582, 1 figure in text, + 12 tables. November 15, 1954. + + 10. A new bat (Genus Pipistrellus) from northeastern Mexico. + By Rollin H. Baker. Pp. 583-586. November 15, 1954. + + 11. A new subspecies of pocket mouse from Kansas. By E. + Raymond Hall. Pp. 587-590. November 15, 1954. + + 12. Geographic variation in the pocket gopher, Cratogeomys + castanops, in Coahuila, Mexico. By Robert J. Russell + and Rollin H. Baker. Pp. 591-608. March 15, 1955. + + 13. A new cottontail (Sylvilagus floridanus) from northeastern + Mexico. By Rollin H. Baker. Pp. 609-812. April 8, 1955. + + 14. Taxonomy and distribution of some American shrews. + By James S. Findley. Pp. 613-618. June 10, 1958. + + 15. The pigmy woodrat, Neotoma goldmani, its distribution + and systematic position. By Dennis G. Rainey and Rollin + H. Baker. Pp. 619-624, 2 figures in text. June 10, + 1955. + + Index. Pp. 625-651. + + + Vol. 8. 1. Life history and ecology of the five-lined skink, Eumeces + fasciatus. By Henry S. Fitch. Pp. 1-156, 26 figures in + text. September 1, 1954. + + 2. Myology and serology of the Avian Family Fringillidae, + a taxonomic study. By William B. Stallcup. Pp. 157-211, + 23 figures in text, 4 tables. November 15, 1954. + + 3. An ecological study of the collared lizard (Crotaphytus + collaris). By Henry S. Fitch. Pp. 213-274, 10 figures + in text. February 10, 1956. + + 4. A field study of the Kansas ant-eating frog, Gastrophryne + olivacea. By Henry S. Fitch. Pp. 275-306, 9 figures in + text. February 10, 1956. + + 5. Check-list of the birds of Kansas. By Harrison B. + Tordoff. Pp. 307-359, 1 figure in text. March 10, 1956. + + 6. A population study of the prairie vole (Microtus + ochrogaster) in northeastern Kansas. By Edwin P. + Martin. Pp. 361-416, 19 figures in text. April 2, 1956. + + 7. Temperature responses in free-living amphibians and + reptiles of northeastern Kansas. By Henry S. Fitch. + Pp. 417-476, 10 figures in text, 6 tables. + June 1, 1956. + + 8. Food of the crow, Corvus brachyrhynchos Brehm, in + south-central Kansas. By Dwight Platt. Pp. 477-498, + 4 tables. June 8, 1956. + + 9. Ecological observations on the woodrat, Neotoma + floridana. By Henry S. Fitch and Dennis G. Rainey. + Pp. 499-533, 3 figures in text. June 12, 1956. + + 10. Eastern woodrat, Neotoma floridana: Life history and + ecology. By Dennis G. Rainey. Pp. 535-646, 12 plates, + 13 figures in text. August 15, 1956. + + Index. Pp. 647-675. + + Vol. 9. 1. Speciation of the wandering shrew. By James S. Findley. + Pp. 1-68, 18 figures in text. December 10, 1955. + + 2. Additional records and extensions of ranges of mammals + from Utah. By Stephen D. Durrant, M. Raymond Lee, and + Richard M. Hansen. Pp. 69-80. December 10, 1955. + + 3. A new long-eared myotis (Myotis evotis) from northeastern + Mexico. By Rollin H. Baker and Howard J. Stains. + Pp. 81-84. December 10, 1955. + + 4. Subspeciation in the meadow mouse, Microtus + pennsylvanicus, in Wyoming. By Sydney Anderson. + Pp. 85-104, 2 figures in text. May 10, 1956. + + 5. The condylarth genus Ellipsodon. By Robert W. Wilson. + Pp. 105-116, 6 figures in text. May 19, 1956. + + 6. Additional remains of the multituberculate genus + Eucosmodon. By Robert W. Wilson. Pp. 117-123, + 10 figures in text. May 19, 1956. + + 7. Mammals of CoAihuila, Mexico. By Rollin H. Baker. + Pp. 125-335, 75 figures in text. June 15, 1956. + + 8. Comments on the taxonomic status of Apodemus peninsulae, + with description of a new subspecies from North China. + By J. Knox Jones, Jr. Pp. 337-346, 1 figure in text, + 1 table. August 15, 1956. + + 9. Extensions of known ranges of Mexican bats. By Sydney + Anderson. Pp. 347-351. August 15, 1956. + + 10. A new bat (Genus Leptonycteris) from Coahuila. By Howard + J. Stains. Pp. 353-356. January 21, 1957. + + 11. A new species of pocket gopher (Genus Pappogeomys) from + Jalisco, Mexico. By Robert J. Russell. Pp. 357-361. + January 21, 1957. + + 12. Geographic variation in the pocket gopher, Thomomys + bottae, in Colorado. By Phillip M. Youngman. + Pp. 363-387, 7 figures in text. February 21, 1958. + + 13. New bog lemming (genus Synaptomys) from Nebraska. + By J. Knox Jones, Jr. Pp. 385-388. May 12, 1958. + + 14. Pleistocene bats from San Josecito Cave, Nuevo Leon, + Mexico. By J. Knox Jones, Jr. Pp. 389-396. + December 19, 1958. + + 15. New Subspecies of the rodent Baiomys from Central + America. By Robert L. Packard. Pp. 397-404. + December 19, 1958. + + 16. Mammals of the Grand Mesa, Colorado. By Sydney Anderson. + Pp. 405-414, 1 figure in text. May 20, 1959. + + 17. Distribution, variation, and relationships of the montane + vole, Microtus montanus. By Sydney Anderson. + Pp. 415-511. 12 figures in text, 2 tables. + August 1, 1959. + + 18. Conspecificity of two pocket mice, Perognathus goldmani + and P. artus. By E. Raymond Hall and Marilyn Bailey + Ogilvie. Pp. 513-518, 1 map. January 14, 1960. + + 19. Records of harvest mice, Reithrodontomys, from Central + America, with description of a new subspecies from + Nicaragua. By Sydney Anderson and J. Knox Jones, Jr. + Pp. 519-529. January 14, 1960. + + 20. Small carnivores from San Josecito Cave (Pleistocene), + Nuevo LeA cubedn, MA(C)xico. By E. Raymond Hall. Pp. 531-538, + 1 figure in text. January 14, 1960. + + 21. Pleistocene pocket gophers from San Josecito Cave, Nuevo + LeA cubedn, MA(C)xico. By Robert J. Russell. Pp. 539-548, + 1 figure in text. January 14, 1960. + + 22. Review of the insectivores of Korea. By J. Knox Jones, + Jr., and David H. Johnson. Pp. 549-578. + February 23, 1960. + + More numbers will appear in volume 9. + + Vol. 10. 1. Studies of birds killed in nocturnal migration. + By Harrison B. Tordoff and Robert M. Mengel, Pp. 1-44, + 6 figures in text, 2 tables. September 12, 1956. + + 2. Comparative breeding behavior of Ammospiza caudacuta + and A. maritima. By Glen E. Woolfenden. Pp. 45-75, + 6 plates, 1 figure. December 20, 1956. + + 3. The forest habitat of the University of Kansas Natural + History Reservation. By Henry S. Fitch and Ronald R. + McGregor. Pp. 77-127, 2 plates, 7 figures in text, + 4 tables. December 31, 1956. + + 4. Aspects of reproduction and development in the prairie + vole (Miorotus ochrogaster). By Henry S. Fitch. + Pp. 129-161, 8 figures in text, 4 tables. + December 19, 1957. + + 5. Birds found on the Arctic slope of northern Alaska. + By James W. Bee. Pp. 163-211, pls. 9-10, 1 figure in + text. March 12, 1958. + + 6. The wood rats of Colorado: distribution and ecology. + By Robert B. Finley, Jr. Pp. 213-552, 34 plates, + 8 figures in text, 35 tables. November 7, 1958. + + 7. Home ranges and movements of the eastern cottontail in + Kansas. By Donald W. Janes. Pp. 553-572, 4 plates, + 3 figures in text. May 4, 1959. + + 8. Natural history of the salamander, Aneides hardyi. + By Richard F. Johnston and Schad Gerhard. Pp. 573-585. + October 8, 1959. + + More numbers will appear in volume 10. + + Vol. 11. 1. The systematic status of the colubrid snake, Leptodeira + discolor GA1/4nther. By William E. Duellman. Pp. 1-9, + 4 figs. July 14, 1958. + + 2. Natural history of the six-lined racerunner, + Cnemidophorus sexlineatus. By Henry S. Fitch. + Pp. 11-62, 9 figs., 9 tables. September 19, 1958. + + 3. Home ranges, territories, and seasonal movements of + vertebrates of the Natural History Reservation. + By Henry S. Fitch. Pp. 63-326, 6 plates, 24 figures + in text, 3 tables. December 12, 1958. + + 4. A new snake of the genus Geophis from Chihuahua, Mexico. + By John M. Legler. Pp. 327-334, 2 figures in text. + January 28, 1959. + + 5. A new tortoise, genus Gopherus, from north-central + Mexico. By John M. Legler. Pp. 335-343. + April 24, 1959. + + 6. Fishes of Chautauqua, Cowley and Elk counties, Kansas. + By Artie L. Metcalf. Pp. 345-400, 2 plates, 2 figures + in text, 10 tables. May 6, 1959. + + 7. Fishes of the Big Blue River Basin, Kansas. By W. L. + Minakley. Pp. 401-442, 2 plates, 4 figures in text, + 5 tables. May 8, 1959. + + 8. Birds from Coahuila, Mexico. By Emil K. Urban. + Pp. 443-516. August 1, 1959. + + 9. Description of a new softshell turtle from the + southeastern United States. By Robert G. Webb. + Pp. 517-525, 2 pls., 1 figure in text. August 14, 1959. + + 10. Natural history of the ornate box turtle, Terrapene + ornata ornata Agassiz. By John M. Legler. Pp. 527-669, + 16 pls., 29 figures in text. March 7, 1960. + + Index will follow. + + Vol. 12. 1. Functional morphology of three bats: Eumops, Myotis, + Macrotus. By Terry A. Vaughan. Pp. 1-153, 4 plates, + 24 figures in text. July 8, 1959. + + 2. The ancestry of modern Amphibia: a review of the + evidence. By Theodore H. Eaton, Jr. Pp. 155-180, + 10 figures in text. July 10, 1959. + + 3. The baculum in microtine rodents. By Sydney Anderson. + Pp. 181-216, 49 figures in text. February 19, 1960. + + More numbers will appear in volume 12. + + + + +Transcriber's Notes + +Except for the typographical corrections listed below, the following +changes were made. The section label (Color and Markings) on page 593 +was changed from italics as those were used to delimit the subsections. +Based on the formatting used for other text in this publication, other +minor typographica changes may also have been made where periods, +commas, etc. were left out or inserted erroneously. + + +Typographical Corrections + + Page Correction + ==== ========================= + 542 Plate 1 a†' Plate 15 + 568 hiberation a†' hibernation + 580 expresssed a†' expressed + 582 rail a†' rain + 590 spical a†' apical + 597 Pl. 11 a†' Plate 19 + 601 mullberry a†' mulberry + 603 an a†' and + 604 monentarily a†' momentarily + 614 detph a†' depth + 640 presssure a†' pressure + 667 retpiles a†' reptiles + + +Text Emphasis + + _Text_ - Italics + + =Text= - Bold + Italics + + + + + + + +End of the Project Gutenberg EBook of Natural History of the Ornate Box +Turtle, Terrapene ornata ornata Agassiz, by John M. 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