The Common snapping turtle is a large freshwater turtle. It is noted for its combative disposition when out of the water with its powerful beak-like jaws, and highly mobile head and neck (hence the specific name serpentina, meaning "snake-like"). These turtles have a rugged, muscular build with a ridged carapace (upper shell), although ridges tend to be more pronounced in younger individuals. The carapace (top of shell) varies in color from black to light brown. Males in this species are larger than females.
The natural range of Common snapping turtles extends from southeastern Canada, southwest to the edge of the Rocky Mountains, as far east as Nova Scotia and Florida. These turtles inhabit rivers, lakes, marshes, shallow ponds or streams. They may also occur in brackish environments, such as estuaries.
Common snapping turtles spend most of their time in the water rather than on land. They are most active at dawn and dusk when doing their hunting. As one of the strategies to ambush the prey these turtles sometimes bury themselves in the mud with only their nostrils and eyes exposed. Common snapping turtles sometimes bask-though rarely observed-by floating on the surface with only their carapaces exposed, though in the northern parts of their range, they also readily bask on fallen logs in early spring. In shallow waters, Common snapping turtles may lie beneath a muddy bottom with only their heads exposed, stretching their long necks to the surface for an occasional breath (their nostrils are positioned on the very tip of the snout, effectively functioning as snorkels). In their environment, Common snapping turtles are at the top of the food chain, thus feeling less fear or aggression in some cases. When they encounter a species unfamiliar to them such as humans, in rare instances, they will become curious and survey the situation and even more rarely may bump their nose on a leg of the person standing in the water. Although snapping turtles have fierce dispositions, when they are encountered in the water or a swimmer approaches, they will slip quietly away from any disturbance or may seek shelter under mud or grass nearby.
Common snapping turtles are omnivores. They consume both plant and animal matter and are important aquatic scavengers. They are active hunters that prey on anything they can swallow, including many invertebrates, fish, frogs, reptiles (including snakes and smaller turtles), unwary birds, and small mammals.
Little is known about the mating system in Common snapping turtles. During the breeding season, males fight each other to get access to females. These turtles mate from April through November, with their peak laying season in June and July. Females travel over land to find sandy soil in which to lay their eggs, often some distance from the water. After digging a hole, the female typically deposits 25 to 80 eggs each year, guiding them into the nest with her hind feet and covering them with sand for incubation and protection. Incubation time is temperature-dependent, ranging from 9 to 18 weeks. Baby snapping turtles are about 2.5 cm long at hatching. They will either leave the nest within a few days and head straight for water or if, in cooler climates, hatchlings will overwinter in the nest. Females, and presumably also males, in more northern populations mature at 15-20 years of age while those in more southern populations reach maturity when they are about 12 years old.
Common snapping turtles are characterized by high and variable mortality of embryos and hatchlings, delayed reproductive maturity, and low reproductive success. Populations of these turtles have declined sufficiently due to pressure from the collection for the pet trade and habitat degradation. Common snapping turtles travel extensively overland to reach new habitats or to lay eggs. Pollution, habitat destruction, food scarcity, overcrowding, and other factors drive snappers to move and it is quite common to find them traveling far from the nearest water source.
According to IUCN, the Common snapping turtle is locally common and widespread throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
These turtles are top predators in their ecosystem; they control populations of various mammals, amphibians, mollusks, reptiles, and insects they prey on. They are also important aquatic scavengers and thus assisting in “natural recycling”.