With large heads and powerful jaws, alligator snapping turtles (Macrochelys temminckii) are the largest freshwater turtles in the world. They can be easily distinguished by the three large pronounced ridges that run from front to back on the carapace. The fact that they have eyes on the sides of their heads makes them unique.
[Picture of an alligator snapping turtle (M. temminckii) that I took while at the Columbus Zoo]
Alligator snapping turtles live in freshwater areas in the southeastern United States. Adults live in deep lakes and ponds, while juveniles are usually found in smaller rivers and streams.
Alligator snapping turtles are hunters and sometimes scavengers. They sit still with their mouth open, using their tongue to lure in fish. Alligator snapping turtles will also eat molluscs, crayfish, insects, leaves, roots, tubers, nuts, and seeds, and aquatic plants, but their diet mainly consists of fish. They may even eat other turtles; in one Louisiana study, turtles were found in the stomachs of just under 80% of all alligator snapping turtles.
By attaching radio transmitters to alligator snapping turtles in Arkansas, Howey and Dinkelacker found how they choose habitats throughout the year. Both males and females showed a high preference for aquatic sites with large amounts of submerged debris and canopy cover. This may be due to increased prey abundance near debris and higher chance of nuts and seeds falling from canopy cover. Also, more cover allows for more places for the alligator snapping turtles to hide from predators. Howey and Dinkelacker also found that both sexes prefer deeper water or stream banks during the summer months for easier thermoregulation. This allows them to sun themselves to warm up, and go underwater to cool off.
AnimalDiversityWeb. (2010, November). Macrochelys temminckii. Retrieved November 29, 2010, from
Howey, C. A. F. & Dinkelacker, S. A. (2009). Habitat Selection of the Alligator Snapping Turtle (Macrochelys temminckii) in Arkansas. Journal of Herpetology, 43(4), 589-596. doi:10.1670/08-105.1