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 Terrapene carolina in the U.S. Terrapene carolina bauri (Florida box turtle) lives on the peninsula of Florida. Terrapene c. major (Gulf Coast box turtle) ranges from the panhandle of Florida westward along the Gulf Coast to eastern Texas. Terrapene c. triunguis (3 toed box turtle) lives 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. Terrapene c. carolina (common box turtle), covering the largest area, lives from Michigan and Maine on the north, and ranges 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 T. c. triunguis and T. c. carolina overlap. (Carr, 1952; Ernst, et al., 1994)
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.
Males are slightly larger on average, the posterior lobe of their plastron is concave, 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, and the posterior lobe of their plastron is flat or slightly convex.
There is some variation between the different subspecies of box turtles. Terrapene c. bauri is roughly 11cm x 8cm 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.
Terrapene c. carolina is 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.
Terrapene c. triunguis is about the same length as T. c. carolina, 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.
Terrapene c. major is the largest at about 18 cm x 12 cm in size. They have a dark brown shell that often has no pattern, or a faint pattern similar to that of bauri. They have dark skin and plastron as well as four toes on the hind feet.
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. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
Terrapene carolina exhibit temperature dependent sex determination. Nests that are 22-27 degrees C tend to be males, and those above 28 degrees tend to be female. Terrapene carolina are well developed at birth (precocial) and grow at a rate of about 1.5 cm 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. (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. Terrapene carolina exhibit temperature dependent sex determination. Nests that are 22-27 degrees C tend to be males, and those above 28 degrees tend to be female.
Terrapene carolina are well developed at birth (precocial) and grow at a rate of about 1.5cm 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. (Carr, 1952; Ernst and Barbour, 1972)
Environmental temperature determines the activity rate of these turtles. Preferred body temperature is between 29 and 38 degrees Celcius.
In the heat of the summer, Terrapene carolina largely restricts their activity to mornings and after rain. 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)
Omnivorous, Terrapene carolina eats 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 are primarily carnivorous while they grow during their first 5-6 years. Adults tend to be mostly herbivorous, but they eat no green leaves. Young often hunt in ponds and streams because the type of food they prefer is easier to catch there, but adults usually feed on land. When confronted with several mealworms, a captive adult picked up each in turn and with a few bites killed or disabled it. Only when all were incapable of escape did the turtle start to feed. This behavior was observed on several occasions when more than one mealworm was offered (Ernst et al., 1994; Carr, 1952; Ernst and Barbour, 1972). (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 are very popular as pets, and they may serve the ecological role of a seed distributor through their eating of berries that contain seeds. They also eat some injurious insects. 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 dangerous to eat due to the possibility of being poisoned, presumably due to the turtle having eaten poisonous mushrooms that don't hurt it, but that retain their ability to poison humans. They sometimes cause damage to tomato, lettuce, cucumber, cantaloupe, and strawberry crops. They sometimes destroy the eggs of ground-nesting birds. They may carry the western equine encephalitis virus in their blood. (Carr, 1952; Ernst and Barbour, 1972; Ernst, et al., 1994)
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)
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.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
flesh of dead animals.
either directly causes, or indirectly transmits, a disease to a domestic animal
a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
A substance that provides both nutrients and energy to a living thing.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
Referring to a burrowing life-style or behavior, specialized for digging or burrowing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.
Animals with indeterminate growth continue to grow throughout their lives.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
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.