Box turtles are North American turtles of the genus Terrapene. Although box turtles are superficially similar to tortoises in terrestrial habits and overall appearance, they are actually members of the American pond turtle family (Emydidae).
The twelve taxa which are distinguished in the genus are distributed over four species. They are largely characterized by having a domed shell, which is hinged at the bottom, allowing the animal to close its shell tightly to escape predators.
- Kingdom: Animalia
- Phylum: Chordata
- Class: Reptilia
- Order: Testudines
- Suborder: Cryptodira
- Family: Emydidae
- Subfamily: Emydinae
- Genus: Terrapene
All Terrapene carolina have a bridgeless, bilobed, hinged plastron (ventral part of shell) that allows box turtles to close their shells almost completely. They have a steep margined, keeled, high-domed, rounded carapace (dorsal part of shell) with variable markings. Concentric growth furrows can be seen on the carapace, although in some older individuals they become very difficult to see. The upper jaw is slightly hooked. The toes are only slightly webbed.
A combination of gradual habitat degradation and loss, and roadkill and other human-caused accidental mortality, combined with the species’ slow growth and very limited reproductive capacity, indicate that the species will continue if not accelerate its gradual decline across much of its range, eventually probably becoming restricted to large stretches of protected or low-impact land. At an estimated population replacement time of 25 years, three generations stretch from the end of the Wild West era up to the suburban sprawl era. Is is currently listed as Near Threatened.
North American box turtles are omnivores with a varied diet, as a box turtle will “basically eat anything it can catch”. Invertebrates (amongst others insects, earth worms, millipedes) form the principal component, but the diet also consists for a large part (reports range from 30-90%) of vegetation.
Populations of Ornate Box Turtles can be numerous, reaching densities of 6.4-15.6 animals per hectare of favourable habitat in Kansas (Legler 1960). The ssp. luteola appears to be uncommon in the Chihuahua and Sonora deserts of the United States, which Milstead and Tinkle (1967) attributed to more arid conditions and the absence of dense plant cover. However, it was perceived as common in the Mexican part of its range.
Because box turtles occupy a wide variety of habitats (which both vary on a day-to-day, season-to-season, but also species-to-species basis), a standard box turtle habitat can not be identified.
Mesic woodlands are a habitat where box turtles are generally found. T. ornata is the only species regularly found in grasslands, but its subspecies the desert box turtle is also found in the semidesert with rainfall predominantly in summer. The single location where Coahuilan box turtles are found is a 360 km2 region characterized by marshes, permanent presence of water and several types of cacti.