The common box turtle (Terrapene carolina) is a species of box turtle with six existing subspecies. It is found throughout the Eastern United States and Mexico. The box turtle has a distinctive hinged lowered shell (the box) that allows it to completely enclose itself. Its upper jaw is long and curved. The turtle is primarily terrestrial and eats a wide variety of plants and animals. The females lay their eggs in the summer. Turtles in the northern part of their range hibernate over the winter. Common box turtle numbers are declining because of habitat loss, roadkill, and capture for the pet trade. The species is classified as vulnerable to threats to its survival by the IUCN Red List. Three U.S. states name subspecies of the common box turtle as their official reptile. Classification Terrapene carolina was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae. It is the type species for the genus Terrapene and has more subspecies than the other three species within that genus. The eastern box turtle subspecies was the one recognized by Linnaeus. The other five subspecies were first classified during the 19th century. In addition, one extinct subspecies, T. c. putnami, is distinguished. Subspecies Parentheses around the name of an authority indicate that he originally described the subspecies in a genus other than Terrapene. Description The common box turtle (Terrapene carolina) gets its common name from the structure of its shell which consists of a high domed carapace (upper shell), and large, hinged plastron (lower shell) which allows the turtle to close the shell, sealing its vulnerable head and limbs safely within an impregnable box. The carapace is brown, often adorned with a variable pattern of orange or yellow lines, spots, bars or blotches. The plastron is dark brown and may be uniformly coloured, or show darker blotches or smudges. The common box turtle has a small to moderately sized head and a distinctive hooked upper jaw. The majority of adult male common box turtles have red irises, while those of the female are yellowish-brown. Males also differ from females by possessing shorter, stockier and more curved claws on their hind feet, and longer and thicker tails. There are six living subspecies of the common box turtle, each differing slightly in appearance, namely in the colour and patterning of the carapace, and the possession of either three or four toes