Natural History of the Ornate Box Turtle, Terrapene Ornata Ornata Agassiz

Part 1

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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

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

28-773

Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz

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

Part 2

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.

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.

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