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ZOO-ology column: Alligator snapper is dinosaur of turtle world

Dec. 18, 2011 at 6:18 a.m.

The inside of the alligator snapping turtle's mouth is dark and there's a built-in lure in the bottom. It looks like a reddish worm.

Sources

Ernst, Carl H. and Roger W. Barbour, Turtles of the World, Smithsonian Institution Press, 1989; Texas Turtle Regulations tpwd.state.tx.us/publications/.../pwd_lf_w7000_1667.pdf; www.arkive.org/; Macrochelys_temminickii - TexasTurtles www.texasturtles.org/Macrochelys_temminckii.html.

By Judie Farnsworth

It lives in the southeastern United States, can exceed 200 pounds, wears spikes and uses a red lure to hunt.

No, it's not cousin Bubba - it's the dinosaur of the turtle world, the alligator snapping turtle.

A spiked shell, hooked, beak-like jaws, oversized claws and a scaled tail, nearly as long as its upper shell (carapace) all add to its prehistoric look.

The carapace has three prominent ridges that run down its back. Their resemblance to an alligator gives this turtle its common name.

The freshwater alligator snapping turtle is one of the largest in the world, certainly in North America. It's found in rivers, lakes, bayous and canals.

These turtles rarely come ashore. Females leave the water to lay and bury their eggs, normally around 50 feet from the water. Mating and egg laying are usually annual spring events with no ruffles and flourishes.

There doesn't seem to be any social niceties. An average of 10 to 50 eggs are left and no parental care is given. Eggs are often found, uncovered and eaten by other animals, like raccoons.

Those turtles that hatch have a dangerous trek back to the water. They may become prey for animals, snakes, birds and even other turtles once they reach the water.

In nature, it's interesting that the animals having the highest potential mortality rates have the greatest number of offspring. This helps secure a species' survival.

Males weigh an average 175 pounds and females an average of 50 pounds. The shell size averages 26 inches. They have been known to live more than 100 years. It takes an average of 12 years to reach maturity.

All snapping turtles hunt and scavenge to some degree, but the alligator snapper is inactive to the extent that greenish algae may cover it, making it almost invisible. It may resemble a pile of rocks. It's most apt to be active at night, but has to surface to breath about every 40 to 50 minutes. During the day it lies quietly at the bottom of the water often with open jaws. The inside of the mouth is dark and there's a built-in lure in the bottom. It looks like a reddish worm. If a fish swims close to investigate, bam - the jaws snap shut. A fish can be swallowed whole, cut in two by the sharp jaws or impaled on the jaw tips.

At rest, the lure is grayish, but becomes filled with blood when used as a lure. Frogs, crabs, snakes, smaller turtles, mammals and aquatic plants are also eaten, but fish are a primary food.

Adult snappers have no natural predators other than humans through illegal hunting. Abandoned trot (fishing) line entanglements often prove lethal and habitat loss is a big factor in their conservational status. They are not known to be overtly aggressive, but if provoked or cornered, will stand their ground. Fingers can easily be amputated by the hugely powerful bite force.

These turtles are protected through much of their range and listed as a threatened species in Texas.

The Education Department at The Texas Zoo has a baby alligator snapping turtle for you to see.

Judie Farnsworth is a longtime volunteer at the Texas Zoo specializing in educational programs.

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