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Adult snapping turtles are large, 20 to 37 cm in carapace length, and males attain larger sizes than females (Congdon et al., 1986; Ernst and Barbour, 1972; Galbraith et al., 1988). In a large oligotrophic lake in Ontario Canada, adult males averaged over 10 kg, whereas the females averaged 5.2 kg (Galbraith et al., 1988). In other populations, the difference in size between males and females often is less (Congdon et al., 1986; Galbraith et al., 1988; Hammer, 1969). They reach sexual maturity at approximately 200 mm in carapace length (Mosimann and Bider, 1960). The cool, short activity season in more northern areas results in slower growth rates and longer times to reach sexual maturity (Bury, 1979).
They are most often found in turbid waters with a slow current (Graves and Anderson, 1987). They spend most of their time lying on the bottom of deep pools or buried in the mud in shallow water with only their eyes and nostrils exposed. Froese (1978) observed that young snapping turtles show a preference for areas with some obstructions that may provide cover or food.
Snapping turtles are omnivorous. In early spring, when limited aquatic vegetation exists in lakes and ponds, they may eat primarily animal matter; however, when aquatic vegetation becomes abundant, they become more herbivorous (Pell, 1941, cited in Graves and Anderson, 1987). Young snapping turtles are primarily carnivorous and prefer smaller streams where aquatic vegetation is less abundant (Lagler, 1943; Pell, 1941, cited in Graves and Anderson, 1987). Snapping turtles consume a wide variety of animal material including insects, crustaceans, clams, snails, earthworms, leeches, tubificid worms, freshwater sponges, fish (adults, fry, and eggs), frogs and toads, salamanders, snakes, small turtles, birds, small mammals, and carrion and plant material including various algae (Alexander, 1943; Graves and Anderson, 1987; Hammer, 1969; ￼Punzo, 1975).
Snappers are most active at night. During the day, they occasionally leave the water to bask on shore, but basking is probably restricted by intolerance to high temperatures and by rapid loss of moisture (Ernst and Barbour, 1972).
Snapping turtles usually enter hibernation by late October and emerge sometime between March and May, depending on latitude and temperature. To hibernate, they burrow into the debris or mud bottom of ponds or lakes, settle beneath logs, or retreat into muskrat burrows or lodges. Snapping turtles have been seen moving on or below the ice in midwinter. Large congregations sometimes hibernate together (Budhabatti and Moll, 1988; Ernst and Barbour, 1972).
Most turtles stay primarily within the same marsh or in one general area from year to year ((Hammer, 1969; Obbard and Brooks, 1981). The summer home range includes a turtle's aquatic foraging areas, but females may need to travel some distance outside of the foraging home range to find a suitable nest site (DeGraaf and Rudis, 1983).