The alligator snapping turtle has a large head and thick shell with three ridges that feature large, spiked scales. In contrast, the common snapping turtle (Chelydra serpentina) has a smoother shell. Snapping turtle have strong, stout heads, powerful jaws, and sharp claws. alligator snapping turtles are opportunistic predators. Their usual diet includes fish, carcasses, mollusks, amphibians, worms, snakes, water birds, crayfish, aquatic mammals, and other turtles. They will also eat aquatic plants. Large alligator snapping turtles have been known to kill and eat American alligators. Like other reptiles, they refuse to eat when the temperature is extremely cold or hot because they cannot digest their meal.