Alligator snapping turtle

The alligator snapping turtle (Macrochelys temminckii) is one of the heaviest freshwater turtles in the world, having been recently proven outweighed by the Hoan Kiem Turtle, a giant softshell turtle. It is often associated with, but not closely related to, the common snapping turtle, which is in the genus Chelydra. The specific epithet temminckii is in honor of Dutch zoologist Coenraad Jacob Temminck.

Although it was once believed to be only one species, a recent study suggests that it is actually three separate species; Macrochelys temminckii, Macrochelys suwanniensis, and Macrochelys apalachicolae.

The alligator snapping turtle is given its name because of its immensely powerful jaws and long, spring-like neck, as well as distinct ridges on its shell that are similar to the rough, ridged skin of an alligator.

Distribution and habitat

The alligator snapping turtle is found primarily in southeastern United States waters. They are found from the Florida Panhandle west to East Texas, north to southeastern Kansas, Missouri, southeastern Iowa, western Illinois, southern Indiana, western Kentucky, and western Tennessee. They are found on the Missouri River at least as far north as the Gavins Point Dam, the southernmost dam on the Missouri River at Yankton, South Dakota, and are featured in the Gavins Point Dam Aquarium. Typically, only nesting females venture onto open land.

Common snapping turtle

The common snapping turtle (Chelydra serpentina) is a large freshwater turtle of the family Chelydridae. Its natural range extends from southeastern Canada, southwest to the edge of the Rocky Mountains, as far east as Nova Scotia and Florida. This species and the larger alligator snapping turtle are the only two species in this family found in North America (though the common snapping turtle, as its name implies, is much more widespread).

The common snapping turtle is noted for its combative disposition when out of the water with its powerful beak-like jaws, and highly mobile head and neck (hence the specific name serpentina, meaning "snake-like"). In water, they are likely to flee and hide themselves underwater in sediment. Snapping turtles have a life-history strategy characterized by high and variable mortality of embryos and hatchlings, delayed sexual maturity, extended adult longevity, and iteroparity (repeated reproductive events) with low reproductive success per reproductive event. Females, and presumably also males, in more northern populations mature later (at 15–20 years) and at a larger size than in more southern populations (about 12 years). Lifespan in the wild is poorly known, but long-term mark-recapture data from Algonquin Park in Ontario, Canada suggest a maximum age over 100 years.

Chelydridae

The Chelydridae are a family of turtles which has seven extinct and two extant genera. The extant genera are Chelydra, the snapping turtles, and Macrochelys. Both are endemic to the Western Hemisphere. The extinct genera are Acherontemys, Chelydrops, Chelydropsis, Emarginachelys, Macrocephalochelys, Planiplastron, and Protochelydra.

Fossil history

The Chelydridae have a long fossil history, with extinct species reported from North America, all over Asia and Europe, far outside their present range. The earliest described chelydrid is Emarginachelys cretacea, known from well-preserved fossils from the Maastrichtian stage of the Late Cretaceous of Montana. Another well-preserved fossil chelydrid is the Late Paleocene Protochelydra zangerli from North Dakota. The carapace of P. zangerli is higher domed than that of the recent Chelydra, a trait conjectured to be associated with the coexistence of large, chelonivorous (i.e., turtle-eating) crocodilians. Another genus, Chelydropsis, contains several well-known Eurasian chelydrid species that existed from the Oligocene to the Pliocene.

Turtle

Turtles are reptiles of the order Testudines (or Chelonii) characterised by a special bony or cartilaginous shell developed from their ribs and acting as a shield. "Turtle" may refer to the order as a whole (American English) or to fresh-water and sea-dwelling testudines (British English).

The order Testudines includes both extant (living) and extinct species. The earliest known members of this group date from 157 million years ago, making turtles one of the oldest reptile groups and a more ancient group than snakes or crocodilians. Of the 327 known species alive today, some are highly endangered.

Turtles are ectotherms—their internal temperature varies according to the ambient environment, commonly called cold-blooded. However, because of their high metabolic rate, leatherback sea turtles have a body temperature that is noticeably higher than that of the surrounding water.

Turtles are classified as amniotes, along with other reptiles, birds, and mammals. Like other amniotes, turtles breathe air and do not lay eggs underwater, although many species live in or around water.

Animal bite

An animal bite is a wound, usually lacerations, caused by the teeth. An animal bite usually results in a break in the skin but also includes contusions from the excessive pressure on body tissue from the bite. The contusions can occur without a break in the skin. Bites can be provoked or unprovoked. Other bite attacks may be apparently unprovoked. Biting is a physical action not only describing an attack but it is a normal response in an animal as it eats, carries objects, softens and prepares food for its young, removes ectoparasites from its body surface, removes plant seeds attached to its fur or hair, scratching itself, and grooming other animals. Animal bites often result in serious infections and mortality. Animal bites not only include injuries from the teeth of reptiles, mammals, but fish, and amphibians. Arthropods can also bite and leave injuries.

Signs and symptoms

Bite wounds can cause a number of signs and symptoms