Alligator Snapping Turtle

Taxobox
name = Alligator Snapping Turtle
status = VU | status_system = IUCN2.3

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image_width = 250px
regnum = Animalia
phylum = Chordata
classis = Reptilia
ordo = Testudines
familia = Chelydridae
genus = "Macrochelys"
species = "M. temminckii"
binomial = "Macrochelys temminckii"
binomial_authority = Troost, 1835
synonyms = "Macroclemmys temminckii"
Boulenger, 1889
"Chelonura temminckii"
Troost, 1835
"Testudo planitia"
Gmelin, 1789The Alligator Snapping Turtle ("Macrochelys temminckii") is one of the largest freshwater turtles in the world. 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. [cite web | url=http://ebeltz.net/herps/biogappx.html | title=Biographies of People Honored in the Herpetological Nomenclature North America | accessdate=2006-07-09]

Distribution and habitat

The Alligator Snapping Turtle is found in the Mississippi River and its tributaries throughout the Southeastern U.S.. They are also found in the Missouri River at least as far north as the Gavins Point Dam at Yankton, South Dakota. The Alligator Snapping Turtle has also been found in New England. It is also present in Indiana on the state's endangered species list. It has been recorded in Morgan County, IN(south east) in 1991 and captured but not recorded, within the last 15 years, in Newton County, IN (north west).

The largest freshwater turtle in North America, the alligator snapper keeps to primarily southern U.S. waters, while the smaller, more aggressive common snapper inhabits lakes and streams from South America to Canada. These turtles can remain submerged for up to an hour, and typically, only nesting females will venture onto open land.

Description

The Alligator Snapping Turtle is characterized by a large, heavy head and a long, thick tail with three dorsal ridges of large scales (osteoderms) giving it a primitive appearance reminiscent of some of the plated dinosaurs. They can be immediately distinguished from the Common Snapping Turtle by the three distinct rows of spikes and raised plates on the carapace, whereas the Common Snapping Turtle 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

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, a form of Peckhamian mimicry. The turtle hunts by lying motionless in the water with its mouth wide open. The vermiform tongue imitates the movements of a worm, luring prey to the turtle's mouth. The mouth is then closed 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. [cite web | url=http://www.tortoise.org/archives/macrocl.html | title=Alligator Snapping Turtle: Giant of the Southeastern States | accessdate=2006-03-26]

Fossil history

Unlike the family Chelydridae as a whole, the genus "Macrochelys" 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).

Diet

Alligator snappers are opportunistic carnivores more often at a young age, but are also scavengers. As they mature they become omnivores and do not pose a threat to fish populations. Fishermen have glorified the species' ability to catch fish and deplete fish populations. Minnows are usually the main source of meat for the species at a young age. They will eat almost anything they can catch. Their natural diet consists primarily of fish and dead fish carcasses (usually thrown overboard by fishermen), invertebrates, carrion, and amphibians, but they are also known to eat snakes, and even other turtles. In captivity they may consume almost any kind of meat provided, including rodents, beef, chicken and pork although these are not always healthy on a day to day basis. Though not a primary food source for them, Alligator snappers have been known to kill actual alligators they have been confined with, such as in a net, small bog, or poorly-planned aquarium display.Fact|date=August 2008

Reproduction and lifespan

Maturity is reached at around 12 years of age. [cite web | url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Macrochelys_temminckii.html | title=Animal Diversity Web: Macrochelys temminickii | accessdate=2008-09-12] 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 10-50 eggscite book |last=Kindersley |first= Dorling |year=2001,2005 |title=Animal |location=New York City |publisher=DK Publishing |isbn=0-7894-7764-5] about 2 months later. The sex of the baby alligator snapping turtles depends on the temperature at which the eggs are incubated. 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. [cite web | url=http://www.nashvillezoo.org/asturtle.htm | title=Nashville Zoo: Alligator Snapping Turtle | accessdate=2006-03-26]

Though their potential lifespans in the wild are unknown, alligator snapping turtles are believed to be capable of living to 150 years of age. In captivity, they typically live from anywhere between 20 to 70 years of age. [cite web | url=http://www.whozoo.org/AnlifeSS2001/serishoo/SRS_AlligatorSnappingTurtle.html | title=WhoZoo: Alligator Snapping Turtle | accessdate=2006-03-26]

In captivity

Alligator snapping turtles are often captive-bred as pets and are readily available in the exotic animal trade. 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 can cause significant harm to a human, easily amputating fingers. [cite web | url=http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=1227 | title=NAS - Species FactSheet | accessdate=2006-03-26] Some states where alligator snapping turtles do not range (such as California) prohibit them from being kept as pets by residents.

Conservation status

The alligator snapping turtle is primarily vulnerable to humans from habitat loss and hunting. Some are also hunted for their carapaces; 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. Soup made from snapping turtle meat is considered by some to be a delicacy.

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 was afforded some international protection by being listed as a CITES III species (which will put limits on exportation from the United States). [cite web | url=http://greennature.com/article2503.html | title=Alligator Snapping Turtle and Map Turtles Gain International Protection | accessdate=2006-03-26]

The alligator snapping turtle is now endangered in several states, including Illinois.

References

External links

* [http://www.astfoundation.org/ Alligator Snapping Turtle Foundation]
* [http://www.chelydra.org/common_alligator_snapping_turtle.html Alliator vs. Common Snapping Turtle - Chelydra.org]