Alligator Snapping Turtle (Macrochelys temminckii): Facts

Appearance

The alligator snapping turtle looks like a survivor from the age of dinosaurs. Its upper shell, the carapace, carries three tall rows of ridged, pointed scales that run from front to back. These ridges, together with the rough skin, gave the animal its name, because they recall the bumpy back of an alligator. The ridges are sharpest in young turtles and slowly wear flatter with age.

The head is huge, wide and triangular, with a strongly hooked upper beak. Unlike its relative the common snapping turtle, the alligator snapper has its eyes on the sides of the head, ringed by a star-shaped fringe of small fleshy points that helps break up the outline of the eye. The tail is long and thick, and the lower shell, the plastron, is small, leaving the legs and neck exposed.

The color is gray, brown, black or olive green. In the wild the shell is often covered in algae, which makes a motionless turtle almost invisible on a muddy river bottom. Hatchlings look like small versions of the adults, with rough, dark shells. Males and females look alike, but adult males grow larger and have a thicker tail base.

How big do alligator snapping turtles get?

Adults usually have a shell 35 to 80 cm (14 to 32 in) long and weigh 8 to 80 kg (18 to 176 lb). Males are larger than females, and turtles heavier than about 45 kg (100 lb) are almost always very old males, since these turtles keep growing slowly throughout life. Field surveys typically find average adult weights of around 13 to 21 kg (30 to 46 lb).

A few captive giants weighed more than 100 kg (220 lb); one long-term resident of the Shedd Aquarium in Chicago reached about 113 kg (249 lb). An often repeated report of a 183 kg (403 lb) turtle from Kansas in 1937 has never been verified. For the full story of records and claims, see how big do alligator snapping turtles get?.

Habitat and range

Alligator snapping turtles are found only in the United States, in river systems that flow into the Gulf of Mexico. Their range stretches from the Florida Panhandle and southern Georgia west to east Texas, and north up the Mississippi Valley to southeastern Kansas, Missouri, southeastern Iowa, western Illinois, southern Indiana, western Kentucky and western Tennessee. Louisiana, Arkansas and Mississippi hold important populations.

They prefer the deepest, slowest water available: large rivers and their backwaters, bayous, oxbow lakes, canals, reservoirs and swamps. Radio-tracking studies show that adults favor spots with plenty of cover, such as sunken trees, root balls, undercut banks and beaver lodges, under a shady canopy of overhanging trees. Hatchlings and juveniles often use smaller streams.

Unlike the widespread common snapper, alligator snappers seldom live in isolated ponds and rarely travel over land. Only nesting females regularly leave the water.

Diet and the tongue lure

The alligator snapping turtle is an opportunistic predator and scavenger. Its best-known trick is a form of aggressive mimicry: it rests on the bottom with its mouth wide open and wiggles a pink, worm-shaped appendage on the tip of its tongue. Fish that come to investigate the “worm” are caught when the jaws slam shut. Read more in how do alligator snapping turtles lure fish?.

The lure is used mostly by younger turtles hunting small fish by day. Large adults need far more food and forage actively at night, also using their sense of smell to find prey. They eat fish, other turtles (especially mud and musk turtles), mussels, snails, crayfish, frogs, snakes, carrion and occasionally water birds or small mammals that swim too close.

Plants matter more than most people expect. One study of stomach contents found that acorns from oaks growing along rivers made up more than half of the diet by volume between spring and fall. Because acorns passed by the turtles can still sprout, researchers think the turtles may help spread oak trees along waterways.

Behavior

Alligator snapping turtles are solitary, slow-moving and secretive. They spend most of their lives on the river bottom and usually surface only to breathe, staying submerged for around 40 to 50 minutes at a time. They are mainly active at night.

These turtles are rarely seen basking in the sun. Instead they regulate their body temperature by moving between deeper and shallower water as the seasons change. In the northern part of the range they become inactive in cold weather, but in the south they may feed on warm winter days.

Each turtle uses a home range along a river stretch of several hundred meters, returning to favorite resting spots under logs and roots. Despite their fearsome looks, they are not aggressive in the water and tend to stay still or move away from disturbance.

Reproduction and life cycle

Alligator snapping turtles mature slowly, at around 11 to 13 years of age. Mating takes place in early spring in the south of the range and in late spring further north. About two months later the female crawls onto land and digs a nest in sandy soil, often around 50 m (165 ft) from the water’s edge, out of reach of floods.

A clutch usually contains about 10 to 50 round eggs. Some females nest every year, others every other year, and there is no parental care after the eggs are buried. Incubation takes about 100 to 140 days, and the hatchlings dig out in late summer or fall. As in many turtles, the sex of each hatchling is decided by the temperature of the nest during incubation, not by sex chromosomes.

Nest success varies greatly from year to year, and many nests are dug up by raccoons and other predators.

Lifespan

How long alligator snapping turtles live in the wild is still uncertain. Their slow growth and late maturity suggest a long life, and claims of turtles living 100 years or more are often repeated, but no wild individual has been reliably aged to that point. The oldest documented alligator snapper in captivity lived about 70 years, and field studies have recorded wild adults of several decades old. See how long do turtles live? for other species.

Predators and threats

Eggs and hatchlings are eaten by raccoons, birds, large fish and other predators, and river otters take young turtles. Once a turtle is large, it has almost no natural enemies.

People are the main threat. Large numbers were harvested for turtle meat and soup in the 20th century, and because adults grow and reproduce so slowly, populations recover very slowly from the loss of big breeding turtles. Other threats include collection for the pet trade, dams and channelization that change river habitats, loss of nesting areas, drowning on fishing lines and the swallowing of fishing hooks.

Conservation status

The IUCN Red List classifies the alligator snapping turtle as Endangered (2025 assessment). Since 2023 it has been listed on CITES Appendix II, which regulates international trade. In 2021 the U.S. Fish and Wildlife Service proposed listing the species as threatened under the Endangered Species Act.

Many states have banned or restricted collecting wild turtles, and several, including Illinois, Indiana, Kentucky and Missouri, list it as endangered under state law. Captive-bred young have been released to restore lost populations; in 2024, for example, turtles bred in Oklahoma were returned to the Neosho River in Kansas.

In 2014, scientists showed that the turtles of the Suwannee River basin in Florida and Georgia form a separate species, the Suwannee alligator snapping turtle (Macrochelys suwanniensis). That split made the range of M. temminckii smaller than once thought.

Myths and facts

Myth: it has the strongest bite of any animal. Its bite is powerful and can cause serious injury, but it is far weaker than the bite of large crocodiles. A 2023 study measured bite forces that rose steeply with body size, from very weak in hatchlings to around 1,900 newtons in the largest turtles tested. Its relative is covered in how strong is a snapping turtle bite?.

Myth: it wipes out fish in a river. Anglers once blamed these turtles for emptying fishing spots, but studies show they eat whatever is common and easy to catch and have little effect on fish populations.

Fact: it is not a close relative of alligators. Despite the name and the armored look, it is a turtle in the snapping turtle family, Chelydridae. See alligator snapping turtle vs common snapping turtle for how the two snappers differ.

Relationship with people

Alligator snapping turtles have long been part of the food and folklore of the American South. Today they are popular with visitors to aquariums and zoos, where their stillness and enormous heads draw crowds.

Turtles released by pet owners have turned up far outside their range, including in Oregon and in several European countries such as Germany, the Czech Republic, Hungary, Italy and England. They are not native there and can harm local wildlife, which is why many countries strictly regulate them. If you meet one in the wild, enjoy it from a distance and leave it in the water.