Prehistoric-looking invasive turtle found in Oregon lake
By Scott Sutherland From Geek Quinox
The discovery of an alligator snapping turtle in an Oregon lake has biologists there worried about potential ecological damage due to this invasive species.
Invasive species are a big problem in the world, as these plants, animals and insects are showing up in places where they’d never be found naturally, and end up causing damage to the local ecosystem. Either the native species have no defenses against the invaders, or the invaders end up eating all the food or taking up all the space/
Most of the time, this is a problem of the invasive species being brought to the area from overseas, but even species from the same country can be a big problem if they’re taken out of their natural habitat.
That’s what the Oregon state Department of Fish and Wildlife had on their hands when a fisherman spotted a large, somewhat scary-looking turtle last Friday. It turned out to be an alligator snapping turtle, and whereas it looked like something out of a dinosaur movie, or at least some exotic species from an equatorial rain forest, it’s actually native to the southeastern United States.
These ‘dinosaurs of the turtle world’, as they’re called, can grow to be over 100 kg, and there was even one report from 1937 of a 183 kg specimen found in Kansas. They do quite well in their native swamps and waterways, and the environment there benefits from them being around. However, outside of those areas, they’re a big problem. Their only ‘natural’ predator is us, so they typically take up the top-spot in any ecosystem they move into, depleting fish populations and then moving on to whatever else is in the area — frogs, toads, snakes, and even ducklings and other turtles. Their powerful bite means that they can even pose a risk of injury to people and pets.
The alligator snapping turtle isn’t considered to be endangered, but it is protected in some states in the US, and the International Union for Conservation of Nature has it on their Red List as ‘vulnerable.’ The main threats to their numbers are over-collection for the exotic pet industry, over-harvesting for their meat and shells, and destruction of their habitat.
Where this particular turtle came from is unknown, but the authorities believe it was probably a pet that was released into the wild when it got too big. I’d like to report a happy ending to this story, but unfortunately, these turtles are not protected in Oregon. Rather than risk any problems from this turtle (and hoping there aren’t any more), the Department of Fish and Wildlife captured and euthanized it.
IMAGE: Biologist Jason Journey holds the invasive alligator snapping turtle caught in Oregon last week.(Photo courtesy: Oregon Department of Fish and Wildlife)
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Alligator Snapping Turtle
From National Zoo
TAXONOMY
Order: Chelonia
Family: Chelydridae
Genus/species: Macroclemys temminckii
DESCRIPTION:
Alligator snapping turtles are the largest freshwater turtles. They weigh between 155 and 175 pounds (70 to 80 kg). They are characterized by three large, pronounced ridges, or keels, that run from the front to the back of the carapace. With powerful jaws and a large head, they are unique among snapping turtles for having eyes on the side of the head. The alligator snapping turtle looks very primitive and has been called the dinosaur of the turtle world.
Alligator snapping turtles spend most of their time in the water, and generally only nesting females venture on land. However, males have been known to bask. They are solitary, and there is very little social structure or parental care. The turtles stay submerged for 40 to 50 minutes at a time, and only go to the surface for air. They are so motionless under water that algae may cover their backs and make the turtles almost invisible to fish.
DISTRIBUTION AND HABITAT:
Alligator snapping turtles are native to the southeastern region of the United States. They are confined to the river systems that drain into the Gulf of Mexico.
They generally live in the deep water of large rivers, canals, lakes, and swamps. Hatchlings and juveniles usually live in small streams.
DIET IN THE WILD:
The alligator snapping turtle is both a scavenger and an active hunter. It most actively forages for food during the night. During the day, it usually lies quietly in the bottom of a dark body of water and opens its jaw to reveal a small pink worm-like lure in the back of its gray mouth. The lure attracts fish, and when the fish enter the jaws, they are either swallowed whole, sliced in two by the sharp jaws, or impaled on the sharp tips of the upper and lower jaws. The alligator snapping turtle eats any kind of fish and also eats frogs, snakes, snails, worms, clams, crayfish, aquatic plants, and other turtles. The turtles feed year round by taking advantage of warm winter days to search for food.
ZOO DIET:
They are fed mice, worms, fish, and prepared diet.
REPRODUCTION:
During reproduction, the male alligator snapping turtle mounts the back of the female. He grasps her shell with all four of his feet and inseminates her. It is unlikely that females reproduce more than once a year, and some females lay eggs in alternate years.
The turtles mate in early spring in Florida and late spring in the Mississippi Valley.
They nest about two months later in a nest about 160 feet (50 m) from the shore. All nests are dug in the sand and clutch success is highly variable. A clutch may contain eight to 52 eggs and incubation takes 3.5 to 4.5 months. Hatchlings, therefore, emerge in the fall.
The sex of the hatchling is determined by incubation temperature and the hatchlings look very much like adults. Sexual maturity occurs in 11 to 13 years.
LIFE SPAN:
They can live between 20 and 70 years in captivity.
STATUS:
There is no special status for the alligator snapping turtle. The main threat to the alligator snapping turtle is people who kill these reptiles for their meat.
Alligator snapping turtles play a role in freshwater ecosystems. Adults are not a source of food for any animals other than humans, but eggs and hatchlings are a source of food for large fish, raccoons, and birds. The adults, however, are important predators. Humans find them valuable for their unique appearance and their meat.
FUN FACTS:
There is an unverified legend that a 403-pound (183 kg) alligator snapping turtle was found in the Neosho River in Kansas in 1937.
For more on this story go to:
http://nationalzoo.si.edu/Animals/ReptilesAmphibians/Facts/FactSheets/Alligatorsnappingturtle.cfm
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