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 on each hind foot. The subspecies Terrapene carolina triunguis is particularly distinctive as most males have a bright red head.
Habitat:Terrapene carolina inhabits open woodlands, pastures, and marshy meadows. It is often found near streams and ponds.
Range: The common box turtle inhabits open woodlands, road sides, road middles, marshy meadows, floodplains, scrub forests and brushy grasslands in much of the eastern United States, from Maine and Michigan to eastern Texas and south Florida. It was once found in Canada in southern Ontario and is still found in Mexico along the Gulf Coast and in the Yucatán Peninsula. The species range is not continuous as the two Mexican subspecies, T. c. mexicana (Mexican box turtle) and T. c. yucatana (Yucatán box turtle), are separated from the US subspecies by a gap in western Texas. Three of the US subspecies; T. c. carolina (eastern box turtle), T. c. major (Gulf Coast box turtle) and T. c. bauri<./i> (Florida box turtle); occur roughly in the areas indicated by their names. T. c. triunguis (three-toed box turtle) is found in the central United States.
Diet: These turtles have an incredibly varied diet of animal and plant matter, including earthworms, snails, slugs, insects, wild berries, roots, flowers, fungi, fish, frogs, salamanders, snakes, birds, eggs, and sometimes even animal carrion (in the form of dead ducks, amphibians, assorted small mammals, and even a dead cow).
Reproduction: The mating season begins in the spring and continues throughout summer to about October. Males may mate with more than one female, or the same female several times over a period of several years.
A female may lay fertile eggs for up to four years after one successful mating. Nesting occurs from May through July. Most nests are started at twilight and finished during the night. Nests are usually dug in sandy or loamy soil, using the hind legs. Then eggs are laid in this cavity and the nest is carefully covered up again. There are 3-8 eggs laid, though usually 4 or 5, and they are elliptical with thin, white, flexible shells roughly 3cm long by 2cm wide. Incubation normally last three months, but this varies according to soil temperature and moisture. Terrapene carolina exhibit temperature dependent sex determination. Nests that are 71.5 to 80.5℉ tend to be males, and those above 82.4℉ tend to be female.
Terrapene carolina are well developed at birth (precocial) and grow at a rate of about 0.5 inches per year during the first five years, at which time they reach sexual maturity. Growth slows down considerably after that but has been reported to continue for at least over 20 years. Some Terrapene carolina are believed to live over 100 years.
Along the borders of the subspecies ranges, there exist populations that are extremely varied due to hybridization between subspecies. Many of these individuals are so varied that identification as a member of a subspecies is impossible.
There is some variation between the courtship rituals of the subspecies. The courtship of Terrapene carolina carolina is divided into three phases: a circling, biting, shoving phase; a preliminary mounting phase; and a copulatory phase. Terrapene carolina major shows courtship and mating that is basically the same as in T. c. carolina, but they sometimes mate in shallow water. Terrapene carolina triunguis and T. c. bauri both have somewhat different rituals, which may represent the ancestral method. Both T. c. triunguis and T. c. bauri males have added the behavior of pulsating their throats. Terrapene carolina triunguis does this in front of the female, and T. c bauri* males climb up on the females' carapace with all four feet and then pulsate. The actual copulation is the same in all subspecies, with the male standing somewhat upright, leaning the concave part of his plastron against the back of the female's carapace. It is in this balanced position during which the male fertilizes the female with his penis. Males sometimes fall backwards after copulation, and if they can't right themselves they die of starvation.
Status: Although the common box turtle has a wide range and was once considered common, many populations are in decline as a result of a number of diverse threats. Agricultural and urban development is destroying habitat, while human fire management is degrading it. Development brings with it an additional threat in the form of increased infrastructure, as common box turtles are frequently killed on roads and highways. Collection for the international pet trade may also impact populations in some areas. The life history characteristics of the common box turtle (long lifespan and slow reproductive rate) make it particularly vulnerable to such threats. The common box turtle is therefore classified as a vulnerable species on the IUCN Red List. The common box turtle is also listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species should be carefully monitored to ensure it is compatible with the species' survival. In addition, many U.S. states now regulate or prohibit the taking of this species.
Disclaimer: ITIS taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. However, it is not a legal authority for statutory or regulatory purposes. While every effort has been made to provide the most reliable and up-to-date information available, ultimate legal requirements with respect to species are contained in provisions of treaties to which the United States is a party, wildlife statutes, regulations, and any applicable notices that have been published in the Federal Register. For further information on U.S. legal requirements with respect to protected taxa, please contact the U.S. Fish and Wildlife Service.
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