There is an unverified legend that a 403 lb alligator snapping turtle was found in the Neosho River in Kansas in 1937.
Alligator snapping turtles use chemosensory cues to locate prey items. They use gular (throat) pumping to draw water in and out to sample the surrounding water for chemicals that have been released by prey species. Adult snapping turtles use this sensory system to hunt and locate mud and musk turtles (Kinosternidae) that have buried themselves into the mud bottom of a body of water.
Communication Channels: visual ; chemical
Perception Channels: visual ; chemical
Alligator snapping turtles are threatened by human exploitation in all U.S. states, but especially in Louisiana. In 1991 the U.S. Fish and Wildlife Services (USFWS) nominated alligator snapping turtles as a candidate to be placed on the Endangered Species list, but the USFWS later concluded in 1999 that they did not warrant protection under the Endangered Species Act. In 2004 the state of Louisiana put a ban on the commercial harvest of M. temminckii anywhere in the state.
US Federal List: no special status
CITES: appendix iii
IUCN Red List of Threatened Species: vulnerable
Alligator snapping turtle hatchlings look very similar to adults. Sex is determined by incubation temperature. Warm temperatures of 29 to 30 degrees Celsius produce 100% females, while slightly lower temperatures (25 to 27 degrees Celsius) yield predominantly males. All other temperatures allow both to develop. Eggs are fertile if they have a clear subgerminal space or if a chalky white spot is on the eggshell.
Development - Life Cycle: temperature sex determination
Alligator snapping turtles have a dangerous bite, but generally don't attack humans unless provoked.
Negative Impacts: injures humans (bites or stings)
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, racoons, and birds. Adults are important predators. Humans find them valuable for their unique appearance and their meat.
Positive Impacts: food
Alligator snapping turtles are both major predators and opportunistic scavengers in their environment. These turtles can impact fish species as well as other turtle species due to their large food consumption, while also helping to clean up decaying organisms in their habitat.
Ecosystem Impact: biodegradation
Alligator snapping turtles are both scavengers and active hunters. They are most active at night, during the day they lie quietly at the bottom of murky water and open their jaws to reveal their tongue, which looks like a small pink worm-like lure in the back of their gray mouth. The lure attracts fish, which are then either swallowed whole, sliced in two by their sharp jaws, or impaled on the sharp tips of the upper and lower jaws. Alligator snapping turtles most frequently feed on fish, molluscs and other turtles. In a Louisiana study turtles were found in the stomachs of 79.82% of all alligator snapping turtles. Macrochelys temminckii have been recorded eating frogs, snakes, snails, worms, clams, crayfish, insects and aquatic plants. They have even been known to eat medium-sized rodents, such as nutria (Myocastor coypus), squirrels, and muskrats (Ondatra zibethicus), and other medium-sized mammals, including opossums (Didelphis virginianus), raccoons (Procyon lotor), and armadillos (Dasypus novemcinctus). The main source of their diet, however, seems to be fish. These turtles feed year-round by taking advantage of warm winter days to search for food in the water and along the shoreline.
Animal Foods: birds; mammals; reptiles; fish; carrion ; insects; mollusks; aquatic crustaceans
Plant Foods: leaves; roots and tubers; wood, bark, or stems; seeds, grains, and nuts
Primary Diet: carnivore (Piscivore )
Macrochelys temminckii is found from northern Florida to southern Georgia and through the Gulf states into Texas. They are also found as far north as Illinois and Kansas. All stable populations are found around larger bodies of water such as the Mississippi River.
Biogeographic Regions: nearctic (Native )
Alligator snapping turtles live in freshwater areas in the southeastern United States. They generally live in the deepest water within their habitat: large rivers, canals, lakes, swamps, and rivers. Hatchlings and juveniles usually live in smaller streams.
Habitat Regions: temperate ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams
Wetlands: marsh ; swamp
Males live from 11 to 45 years with an average age of 26 years. Females live from 15 to 37 years with an average of 23 years. Alligator snapping turtles can live a very long time in captivity; the oldest known individual in captivity was 70 years old.
Range lifespan
Status: wild: 11 to 45 years.
Range lifespan
Status: captivity: 70 (high) years.
Typical lifespan
Status: wild: 11 to 45 years.
Average lifespan
Status: captivity: 70.3 years.
Alligator snapping turtles are the largest freshwater turtles in the world. They are characterized by three large, pronounced ridges that run from the front to the back of their carapace. They have powerful jaws, large heads, and are unique among snapping turtles for having eyes on the side of their heads. Alligator snapping turtles are primitive in appearance.
Range mass: 70 to 80 kg.
Range length: 79 to 101 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: male larger
The only known predators of adults are humans, but eggs and hatchlings are a source of food for large fish, raccoons, and birds.
Known Predators:
Anti-predator Adaptations: cryptic
During mating, male alligator snapping turtles mount the back of the female. He grasps her shell with all four feet to inseminate.
Mating System: polygynandrous (promiscuous)
It is unlikely that females reproduce more than once a year, some females lay eggs on an alternate-year basis. These turtles mate in early spring in Florida and late spring in the Mississippi Valley. They lay eggs in a nest about two months later in a nest hole dug approximately 50 m from a body of water. All nests are dug in the sand and clutch success is highly variable. A clutch may contain 8 to 52 eggs and incubation takes 100 to 140 days. Hatchlings emerge in the fall. Sexual maturity is reached by both sexes at 11 to 13 years of age.
Breeding interval: Alligator snapping turtles breed once yearly.
Breeding season: These turtles mate in early spring in Florida and late spring in the Mississippi Valley.
Range number of offspring: 8 to 52.
Range gestation period: 100 to 140 days.
Range age at sexual or reproductive maturity (female): 11 to 13 years.
Range age at sexual or reproductive maturity (male): 11 to 13 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average number of offspring: 30.
Besides the act of mating, males invest no additional time or energy towards parenting. Once females dig a nest and lay eggs (9 to 52 per clutch), they invest no additional resources. Juvenile turtles are independent upon hatching.
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
