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.