Top: A shell of T. o. ornata (× ½) 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.