snapping turtle, large, aggressive New World freshwater turtle. The two snapping turtle species are the sole members of the family Chelydridae. Snapping turtles prefer quiet, muddy water. They spend most of their time submerged, surfacing periodically to breathe. They feed on fish and other aquatic animals as well as on vegetation and decaying matter; they are valuable scavengers. They have long necks, powerful jaws, and fierce dispositions, lunging at aggressors and biting them. The common snapping turtle, or snapper ( Chelydra serpentina ), is found from SE and S central Canada to NE South America. The adult is often over 18 in. (45 cm) long and weighs over 30 lb (14 kg); some specimens weigh twice as much. The alligator snapper ( Macrochelys temmincki ) is found in the SE United States and the Mississippi valley. One of the world's largest turtles, it may reach a length of 30 in. (75 cm) and weigh 200 lb (90 kg). It has a muscular, wormlike projection on the tongue, which it uses as a fishing lure as it lies concealed in the mud of a river bottom. Snapping turtles lay their eggs in the ground in early summer, often at some distance from water. The eggs, about 20 in a clutch, hatch after a 10-week incubation, and the young find their way to water. Snapping turtles are classified in the phylum Chordata, subphylum Vertebrata, class Reptilia, order Chelonia, family Chelydridae.