The alligator snapping turtle (Macrochelys temminckii ) is a species of turtle in the family Chelydridae. M. temminckii is one of the heaviest freshwater turtles in the world. The alligator snapping turtle is given its common name because of its immensely powerful jaws and long, spring-like neck. The inside of the turtle's mouth is camouflaged, and it possesses a vermiform (i.e., "worm-shaped") appendage on the tip of its tongue used to lure fish, a form of Peckhamian mimicry. The turtle hunts by lying motionless in the water with its mouth wide open. The vermiform tongue imitates the movements of a worm, luring prey to the turtle's mouth. The mouth is then closed with tremendous speed and force, completing the ambush.