Alligator Snapping Turtle
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| Macrochelys temminckii Troost, 1835 |
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Macroclemmys temminckii |
The Alligator Snapping Turtle (Macrochelys temminckii) is the largest freshwater turtle in North America. It is a larger and slightly less aggressive relative of the Common Snapping Turtle. The epithet temminckii is in honor of Dutch zoologist Coenraad Jacob Temminck.[1]
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[edit] Distribution & Habitat
Alligator snapping turtles are found predominantly in the watershed of the Mississippi River in the United States, ranging through the states of Kansas, Illinois, Missouri, Oklahoma, Arkansas, Alabama, Mississippi, Louisiana and in southeastern Iowa, western Tennessee, western Kentucky, eastern Texas, northwestern and southwestern Georgia, and northern Florida. They are also found in the Missouri River at least as far north as the Gavins Point Dam at Yankton, South Dakota.
Although rare further north, the alligator snapping turtle has been found as far north as the southern tip of Ontario in Canada. There is a population of them within a swamp near Glencoe, Ontario. It was confirmed by researchers from the University of Western Ontario who investigated claims of a dead 48 inch/125 cm (nose to tail) turtle that was hit during the evening on a highway near the swamp. They were confirmed to be alligator snapping turtles, with at least eight that are fully mature in the relatively small swamp and creek.[citation needed]
Like the common snapping turtle, the alligator snapping turtle lives in a primarily aquatic environment, such as slow-moving streams, lakes, or swamps. Typically only nesting females will venture onto land. Alligator snappers are capable of staying submerged for as long as 50 minutes at a time.
[edit] Description
The alligator snapping turtle is characterized by a large, heavy head and a thick tail with three dorsal ridges of large scales giving it a primitive appearance reminiscent of some of the plated dinosaurs. They can be distinguished from the common snapper by the three distinct ridges on the carapace, whereas the common snapper has a smoother carapace. They are a solid gray, brown, black, or olive-green in color, and often covered with algae. They have radiating yellow patterns around the eyes, serving to break up the outline of the eye and keep the turtle camouflaged. Their eyes are also surrounded by a star-shaped arrangement of fleshy filamentous "eyelashes".
There is an unverified report of a 403-pound alligator snapping turtle found in the Neosho River in Kansas in 1937,[2] but the largest one actually on record is 236 lb, and housed at Brookfield Zoo in Chicago, Illinois. They generally do not grow quite that large. Average adult size is around 26 inches shell length with a weight of 175 lb. Males are typically larger than females.[3]
The inside of the turtle's mouth is camouflaged, and it possesses a vermiform (literally, "worm-shaped") appendage on the tip of its tongue used to lure fish. The turtle hunts by lying motionless in the water with its mouth wide open. The vermiform tongue imitates the movements of a worm, and can lure prey into the turtle's mouth. The alligator snapping turtle then closes its mouth with tremendous speed and force, completing the ambush.
The alligator snapping turtle possesses extraordinary bite strength, and can be quite aggressive when cornered. These turtles must be handled with extreme care. [4]
[edit] Fossil History
Unlike the family Chelydridae as a whole, the genus Macroclemys is exclusively North American and is generally considered to contain three valid species: the extant M. temminckii and the extinct M. schmidti and M. auffenbergi (described from the early middle Miocene of Nebraska and the middle Pliocene of Florida, respectively).
[edit] Diet
Alligator snappers are primarily opportunistic carnivores, but are also scavengers. They will eat almost anything they can catch. Their natural diet consists primarily of fish, invertebrates, carrion, and amphibians, but they are also known to eat snakes, aquatic plants, and even other turtles. In captivity they may consume almost any kind of meat provided, including rodents, beef, chicken and pork.
[edit] Reproduction & Lifespan
Maturity is reached at around 12 years of age. Mating takes place yearly; early spring in the southern part of their total range, and later spring in the north. The female builds a nest and lays a clutch of 9-52 eggs about 2 months later. The sex of the baby alligator snapping turtles depends on the temperature at which the eggs are incubated. High temperatures yield males whereas lower temperatures yield females.[citation needed] Nests are typically excavated at least 50 yards from the water's edge to prevent them from being flooded and drowned. Incubation takes from 100 to 140 days, and hatchlings emerge in the early fall.[5]
Though their potential lifespans in the wild are unknown, alligator snapping turtles are believed to be capable of living to 100 years of age. In captivity, they typically live from anywhere between 20 to 70 years of age. [6]
[edit] In Captivity
Alligator snapping turtles are often captive-bred and are readily available in the exotic animal trade, and are frequently kept as pets. Unfortunately, due to their potential size and specific needs, they do not make particularly good pets for all but the most experienced aquatic turtle keepers. Due to sheer size, handling adult specimens can pose significant problems. Despite their reputation, they are typically not prone to biting, but when antagonized are quite capable of delivering a bite with their powerful jaws which cause significant harm to a human, easily amputating fingers. Some states where alligator snapping turtles do not range (such as California) prohibit them from being kept as pets by residents.
[edit] Conservation Concerns
The alligator snapping turtle is primarily vulnerable to humans from habitat loss and hunting. Some are also hunted for their shells; the plastron of the turtle is valued by some because of its shape as a cross. There are accounts of large (50+ lb) turtles being caught both purposefully and accidentally on recreational fishing lines called "trot lines." Abandoned trot lines are thought to be even more dangerous to turtles. Many people consider soup made out of the alligator snapping turtle's meat to be a delicacy. A famous Louisiana dish is turtle sauce piquante.
This turtle is protected from collection throughout much of its range. The IUCN lists it as a threatened species, and as of June 14, 2006 it will be afforded some international protection and be listed as a CITES III species (which will put limits on exportation from the United States).[7]
[edit] In Popular Culture
An alligator snapping turtle appears in the movie Teenage Mutant Ninja Turtles II: The Secret of the Ooze. The turtle has mutated into a giant villain named Tokka.
[edit] References
- ^ Biographies of People Honored in the Herpetological Nomenclature North America. Retrieved on July 9, 2006.
- ^ Smithsonian National Zoological Park: Alligator Snapping Turtle. Retrieved on March 26, 2006.
- ^ Alligator Snapping Turtle: Giant of the Southeastern States. Retrieved on March 26, 2006.
- ^ Alligator Snapping Turtle: Giant of the Southeastern States. Retrieved on March 26, 2006.
- ^ Nashville Zoo: Alligator Snapping Turtle. Retrieved on March 26, 2006.
- ^ WhoZoo: Alligator Snapping Turtle. Retrieved on March 26, 2006.
- ^ Alligator Snapping Turtle and Map Turtles Gain International Protection. Retrieved on March 26, 2006.
