Alligator snapping turtle

Physical features

• The alligator snapping turtle is the largest freshwater turtle in North America. They can grow up to three feet long (carapace length) and average over 100 pounds, though some have grown as large as 220 pounds.

• Males attain much larger sizes than females and can be more than double the size of females of similar age.

• These turtles have very large heads, powerful jaws, a hook-shaped beak, and strong, heavily clawed legs. The shell has three pronounced ridges which run from front to back on the carapace and a very reduced plastron.

• The name “alligator snapping turtle” comes from their unusual physical features, largely their long, ridged tails, which loosely resemble those of alligators. They have also been called “loggerheads” because of their large heads.

• Alligator snapping turtles often sit on the bottom of rivers and streams with their mouths open, wiggling their tongue, which is a small, pink, worm-like structure found in the back of the mouth. This unusual appendage acts as a lure to attract prey. 

• Because these turtles remain motionless underwater for long periods, their backs can become covered with algae and other aquatic plants. This provides excellent camouflage, making them almost invisible to predators and prey.

Diet: Carnivore

• Wild – Primarily eat fish, but may also feed on mollusks, small mammals, snails, insects, aquatic plants, and other turtles. In addition to live prey, they also eat decaying organisms.

• Zoo – Fish, rodents, quai, chicken, crayfish

Reproduction

• Alligator snapping turtles reach sexual maturity at 11 to 13 years.

• They mate once per year in early to late spring, depending on their geographic location. During mating, the male will mount the back of the female and grasp her with all four feet.

• About two months later, the female lays eggs in a nest hole dug approximately 50 yards from a body of water. A clutch typically includes 10 to 50 eggs which incubate for 100 to 140 days. Some females lay eggs only every other year.

• The sex of hatchings is determined by the prevailing temperature during the incubation period. Warmer temperatures produce females, while cooler temperatures produce males.

• Once the act of mating is complete, males invest no time or energy in parenting. Once females dig a nest and finish laying, the eggs are left to hatch on their own. After hatching, juveniles are completely independent and quickly make their way to the water.

Interpretive Information

• Alligator snapping turtles are solitary animals which spend most of their lives in the water, coming up to breathe every 40 to 50 minutes. Aquatic turtles have mechanisms which allow them to obtain oxygen while underwater for long periods.

• Typically, only egg-laying females go on land in order to dig nests.

• These turtles are both active and passive hunters. At night, they actively forage for food. During the day, they rest at the bottom of the water with their mouths open waiting for unsuspecting prey.

• Fish and turtles often swim directly into the turtle’s mouths, attracted by the lure of their unusual tongues, which looks like small, pink worms.

• These turtles can locate prey using chemosensory cues. By drawing water in and out of their throats, they can sample the surrounding area for chemicals released by prey species.

• In one study, 80% of alligator snapping turtles were found to have remains of other turtles in their stomachs.

• Studies over the past decade have determined that the widespread alligator snapping turtle comprises at least two (perhaps three) distinct species. These are the (western) alligator snapping turtle (Macrochelys temminckii), the controversial Apalachicola alligator snapping turtle (M. apalachicolae), and the Suwannee alligator snapping turtle (M. suwanniensis).

Updated March 2024