The Alligator snapping turtle (Macrochelys temminckii) is a large species of turtle in the family Chelydridae. The species is one of the heaviest freshwater turtles in the world. It is also the largest freshwater species of turtle in North America. The specific epithet temminckii is in honor of Dutch zoologist Coenraad Jacob Temminck.
The Alligator snapping turtle is given its common name because of its immensely powerful jaws and distinct ridges on its shell that are similar in appearance to the rough, ridged skin of an alligator. Alligator snapping turtles have a large, heavy head, and a long, thick shell with three dorsal ridges of large scales (osteoderms), giving them a primitive appearance reminiscent of some of the plated dinosaurs. The turtles are solid gray, brown, black, or olive-green in color, and often covered with algae. They have radiating yellow patterns around their eyes, serving to break up the outline of the eyes to keep the turtle camouflaged. Their eyes are also surrounded by a star-shaped arrangement of fleshy, filamentous "eyelashes".
Alligator snapping turtles are 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. Alligator snapping turtles live in rivers, lakes, and canals.
Alligator snapping turtles spend most of their lives in water and only nesting females venture onto open land. They are solitary creatures. These turtles most often hunt at night, however, they may also feed during the day. By day, they may try to attract fish and other prey by sitting quietly at the bottom of murky water and letting their jaws hang open to reveal their tongues, which look like small, pink, worm-like lures in the back of their gray mouths, and lure the prey into striking distance. Small fish, such as minnows, are often caught in this way by younger Alligator snapping turtles, whereas adults must eat a greater quantity per day and must forage more actively. These turtles are able to stay submerged for 40-50 minutes before surfacing for air and will even hibernate during winter at the bottom of ponds and lakes. When underwater Alligator snapping turtles may stay so motionless that algae can cover their backs and make turtles almost invisible to fish.
Alligator snapping turtles are almost entirely carnivorous. Their natural diets consist primarily of fish and fish carcasses, mollusks, carrion, and amphibians. They also eat snakes, crayfish, worms, water birds, aquatic plants, other turtles, and sometimes even Alligators.
Alligator snapping turtles are polygynandrous (promiscuous) which means that both males and females mate with several partners. Their breeding season takes place yearly, in 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 eggs about two months later. The gender of the young 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. They are independent at birth and don't need parental care. Young Alligator snapping turtles reach reproductive maturity at around 12 years of age.
The main threats to Alligator snapping turtles include collection for the exotic pet trade, overharvesting for their meat, pollution, and habitat destruction.
The IUCN Red List and other sources don’t provide the number of the Alligator snapping turtle total population size. Currently, this species is classified as Vulnerable (VU) on the IUCN Red List.
Alligator snapping turtles are very important as they are the main predators and scavengers in their environment. These turtles help control populations of their main prey species and also help to clean up their habitat by feeding on carrion.