One of North America’s most aquatic turtles (2), the common snapping turtle spends much of its time lying on the bottom of a water body or buried in mud in shallow water (2) (3) (5) (6). Although this species is seldom seen basking (2) (5), by day the common snapping turtle can often be seen floating lazily just below the water’s surface (2) (5) (6). Despite being a capable swimmer, the common snapping turtle tends to move by walking along the bottom of a pond or other water body (5).
The common snapping turtle is an omnivorous reptile (2) (6), and eats almost anything it can fit into its sharp jaws (6). Its extremely varied diet includes a wide selection of invertebrates such as worms, leeches, bivalves, snails, shrimp, crayfish and crabs (6) (7). Insects, including beetles and butterflies, are also frequently taken (6), as are fish, amphibians, other small turtles, snakes, small mammals and even birds (3) (6). This bold reptile has even been reported to steal fish from fishermen’s lines (6). The common snapping turtle also eats algae and plant material (1) (3) (5) (6), and is known to scavenge on carrion (1) (2) (5) (6). Hatchling common snapping turtles generally feed on worms, fish and tadpoles (7).
While young common snapping turtles actively forage for food, adults tend to employ a sit-and-wait strategy, ambushing prey as it swims past (5). Prey may be stalked slowly, and the common snapping turtle claims its prize with a rapid extension of its head and neck (5) and a strong bite which is capable of tearing flesh (6).
Most common snapping turtles enter hibernation by late October (6), overwintering at the bottom of permanent, generally shallow waters, buried under the mud or hiding beneath debris (2). Hibernation usually ends around April, but this varies depending on the location. In the summer, some common snapping turtles may aestivate if waterways have dried up, although others simply migrate to wetter areas (6).
The male common snapping turtle matures at a carapace length of around 18 to 19 centimetres, and the female at around 20 to 22 centimetres (6). Over most of its range, the common snapping turtle mates from late March to November, although in southern Florida this species may mate throughout the year (6). Some courtship behaviour has been described, but this tends to vary between populations. To mate, the male common snapping turtle mounts the female (2) (5) (6), gripping hard with its feet. The male may bite the female on the head and neck, and places its chin over the female’s snout (5) (6).
Over much of North America, the main nesting period of this species is between mid-May and mid-June, although this can be earlier in the south and later in the north (6). Using its hind feet (6), the female common snapping turtle digs a flask-shaped nest (2) (5), usually in relatively loose sand, vegetable debris, or even sawdust at old mills (6). In most populations of the common snapping turtle, only one clutch is laid per breeding season (2) (6) (7), although in Florida, C. s. osceola may lay two to four clutches per year. Once a clutch has been laid, the female covers up the nest (6).
The white, spherical eggs of the common snapping turtle have a tough, leathery shell (2) (6), and are roughly the size of a ping-pong ball (7). A clutch consists of between 25 and 45 eggs (6), which are usually incubated for 75 to 95 days (1) (6). The sex of the common snapping turtle hatchlings is determined by the temperature at which the eggs were incubated (2) (3) (6) (8), with warmer incubation temperatures producing female turtles, and cooler temperatures producing males (6).