All Terrapene carolina hinged plastron (the part of shell under a turtle's belly) that allows box turtles to close their shells almost completely. They have a high-domed, rounded carapace (the part of shell above a turtle's back) with variable markings. The upper jaw is slightly hooked. The toes are only slightly webbed.
Males are generally slightly larger than females on average and the claws on their hind legs are short, thick, and curved. Males also have thicker and longer tails. Females' rear claws are longer, straighter, and more slender.
There is some variation between the different subspecies of box turtles. Florida box turtles are roughly 11 cm x 8 cm in size with bright yellow markings on their dark brown carapace in the shape of lines. The plastron also has lines, as does the head. They have three toes on their hind feet.
Common box turtles are about 15 cm x 10 cm in size with highly variable orange or yellow markings on their brown carapace. They have four toes on their hind feet.
Three-toed box turtles are about the same length as common box tutrtles, or a little longer, but with a more narrow shell. They have a tan or olive carapace with darker seams and some vague markings. Their plastron is a lighter yellowish color. They have orange, red, or yellow spots on their head and forelimbs, and males heads are completely red.
Gulf Coast box turtles are the largest at about 18 cm x 12 cm. They have a dark brown shell that often has no pattern, or a faint pattern similar to that of Florida box turtles. They have dark skin and plastron as well as four toes on the hind feet. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
Exclusively North American, box turtles are found in the eastern United States, ranging from southern Maine to Florida along the East Coast, and west to Michigan, Illinois, eastern Kansas, Oklahoma, and Texas. Due to its popularity as a household pet, Terrapene carolina is sometimes found far outside its normal geographic range.
There are four subspecies of box turtles in the U.S. Florida box turtles live on the peninsula of Florida. Gulf Coast box turtles range from the panhandle of Florida westward along the Gulf Coast to eastern Texas. Three-toed box turtles live in the Mississippi River Valley from northern Missouri southward across southeastern Kansas and eastern Oklahoma into south-central Texas; and southeastward across western Tennessee and Georgia to the coastal lowlands. Common box turtles, covering the largest area, range from Michigan and Maine on the north, south to the boundaries of the other subspecies. Very little overlap occurs between the ranges of the subspecies of Terrapene carolina, except for a region in Mississippi and Alabama where common box turtles and three-toed box turtles overlap. (Carr, 1952; Ernst, et al., 1994)
Box turtles hatch as males or females depending upon the temperature of their nest. Nests that are 22-27 degrees C tend to be males, and those above 28 degrees tend to be female. Box turtles are well developed at birth and grow at a rate of about 1.5 cm per year during the first five years, at which time they are mature adults. 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. (Carr, 1952; Ernst, et al., 1994)
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. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
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. Box turtles are well-developd when they hatch. (Carr, 1952; Ernst, et al., 1994)
Box turtles' activity levels depend upon the temperature of their surroundings. They prefer when their body temperature is between 29 and 38 degrees Celcius.
In the heat of the summer, Terrapene carolina is most active in the morning or after it rains. When it gets too hot, they hide under decaying logs and leaves, crawl into mammal burrows, or in mud. When it is very hot, they go into shady pools and puddles to cool off.
In the spring and fall, they may be out foraging during all daylight hours, and they sometimes bask in the sun to get warm. Terrapene carolina are diurnal and scoop out a shallow indentation in which to spend the night.
In the northern regions, Terrapene carolina go into hibernation in October or November, but further south, they remain active later in the year. To hibernate, they burrow as much as two feet deep into loose earth, mud, stream bottoms, old stump holes, or mammal burrows. They may return to the same place to hibernate in successive years and sometimes more than one turtle hibernates in the same hibernacula. They usually emerge from hibernation in April. They sometimes wake up and find a new hibernacula on warm days in the winter.
When frightened, box turtles retract their head, tail, and limbs into their shell and clamp it shut. They wait in this position until the perceived threat is thought to be gone. While juveniles have several predators, very few species can prey effectively on adults due to this defense technique. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
Terrapene carolina usually have a home range with a diameter of 250 yds or less in which they normally stay. Occasionally they journey out from their preferred area, but biologists who study this species do not know why. Home ranges of different individuals overlap frequently, regardless of age or sex. The turtles are often found together and show no agression towards each other. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
Box turtles are omnivores, and eat a wide variety of food including snails, insects, berries, fungi, slugs, worms, roots, flowers, fish, frogs, salamanders, snakes, birds, and eggs indiscriminately. They have been observed eating carrion, feeding on dead ducks, amphibians, assorted small mammals, and even a dead cow. Their preference varies greatly by season but there is one definite trend. Young turtles mainly eat animal material while they are growing. Older adults eat mainly plant material. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
While juveniles have several predators, very few species can prey effectively on adults due to their ability to close their shells. (Ernst, et al., 1994)
This species eats a wide variety of animals, so may effect various prey populations. Also, box turtles may disperse seeds as they eat berries of different kinds of plants.
Box turtles eat some fungi that are poisonous to people. Therefore, box turtles may be dangerous to eat dif they have the poisons from the fungi in them. Box turltes sometimes cause damage to tomato, lettuce, cucumber, cantaloupe, and strawberry crops. They sometimes destroy the eggs of ground-nesting birds. Also they may carry the western equine encephalitis virus in their blood. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
Box turtles are very popular as pets, and they also eat some pestinsects. The Iroquois and other Native Americans used them for food, medical, ceremonial, burial, and hunting purposes. (Ernst and Barbour, 1972; Ernst, et al., 1994)
Terrapene carolina are not considered endangered at the national level in the United States, Canada, or Mexico, although several U.S. states, including Michigan, New Hampshire, Massachusetts, and Connecticut, list T. carolina as a species of special concern. It is considered endangered in Maine. There is evidence that some populations are in decline due to habitat loss, road mortality, and collection for the pet trade. They are listed as lower risk by the IUCN and they are in CITES appendix II. (Ernst, et al., 1994; "", 2005)
Box turtles are often mistaken for tortoises, but they are indeed more closely related to turtles. Box turtles are most famous for their hinged shell, which allows them to retract almost completely into their bony armor to hide from danger. This shell has great regernerative powers. A case was reported in which the carapace of a badly burned box turtle underwent complete regeneration. (Carr, 1952; Ernst and Barbour, 1972)
Matthew Wund (editor), University of Michigan-Ann Arbor.
Steven Niedzielski (author), University of Michigan-Ann Arbor.
NatureServe. 2005. NatureServe Explorer. Accessed August 16, 2005 at http://www.natureserve.org/explorer/.
Carr, A. 1952. Handbook of Turtles. Ithaca, New York, USA: Cornell University Press.
Ernst, C., R. Barbour, J. Lovich. 1994. Turtles of the United States and Canada. Washington, D.C., USA: Smithsonian Institution Press.
Ernst, C., R. Barbour. 1972. Turtles of the United States. Lexington, Kentucky, USA: University Press of Kentucky.