Snapping Turtle. Chelydra serpentine

Description: Carapace length up to 47 cm. Carapace with three prominent longitudinal keels, oval in outline with serrated posterior margin. Plastron cruciform (cross-shaped), greatly reduced. Head large, jaws hooked, neck extremely long and bearing numerous warty tubercles. Limbs are powerful and strongly clawed. Tail long, with dorsal crest of paired spines. Coloration generally olive, dark brown or black, with somewhat lighter, often greenish ventral surface.

Variation: As the animals become older the carapace becomes smoother. Skin colour varies from brown to grey. The females are smaller than the males and have a shorter preanal region of the tail. Hatchlings have an almost round carapace, which is 25-30 mm long. There may be a pattern on this, which disappears as maturity approaches.

Natural history: Highly aquatic. Generally prefers standing or slow- flowing waters with soft bottoms and aquatic vegetation. They spend much of their time on the bottom in shallow waters, or floating just beneath the surface. They are generally more active at night. Females generally travel further and occupy larger home ranges than do males. In Montana, snapping turtles hibernate in mud under the water from October to May. They accept a highly varied diet and typically take fish, frogs, crustaceans, reptiles, birds, plants and carrion. They will also eat various types of algae. This is a highly aggressive species which bites and produces a pungent musk as a defence. Snapping turtles do not appear to be strictly territorial, but aggressive interactions may affect individual spacing.

Reproduction: Females mature at eleven to sixteen years in the north-central U.S.A. Mating occurs in spring or early summer and eggs are laid between May and October. From eight to eighty eggs are placed in shallow pits. Incubation temperature of eggs determines sex. Temperatures of 22-28°C produce males, and higher or lower temperatures result in females. In the United States, hatching takes place after approximately four months. Survivorship of eggs and hatchlings is low, but near 100 percent for adults.

Distribution: Introduced in the Battle River area in Alberta. Naturally occurring throughout the eastern United States and parts of southern Canada. In the west, it extends into extreme southwestern Saskatchewan and adjacent north central Montana. It may occur naturally in the Milk River or in creeks to the south of the Cypress Hills.

Remarks: From two to four subspecies of snapping turtles are recognized. Only Chelydra serpentina serpentina occurs in northern North America. No specimens confirm the presence of Chelydra in Alberta, but Ernst and Barbour (1989) list the range as including the southeastern part of the province. This species may be dangerous to handle but may be safely picked up by the tail if held at arm's length from the body. It is of considerable economic importance, especially in eastern North America, where it forms the basis of most turtle soups.

Significant references: Christiansen and Burken 1979; Congdon et al. 1992, 1994; Dansereau et al. 1958; Ernst and Barbour 1972; Galbraith and Brooks 1986; Galbraith et al. 1987; Hammer 1971; Mosimann and Bider 1960; Obarrd and Brooks 1979, 1981; Pettit et al. 1995; Powell et al. 1997; Raney and Josephson 1954; Sexton 1958; White and Murphy 1973; Yntema 1979.