Common snapping turtle

The common snapping turtle Chelydra serpentina is a large freshwater turtle of the family Chelydridae. Its natural range extends from southeastern Canada, southwest to the edge of the Rocky Mountains, as far east as Nova Scotia and Florida. This species and the larger alligator snapping turtle are the only two species in this family found in North America (though the common snapping turtle, as its name implies, is much more widespread). The common snapping turtle 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. In water, they are likely to flee and hide themselves underwater in sediment.

 Snapping turtles have a life-history strategy characterized by high and variable mortality of embryos and hatchlings, delayed sexual maturity, extended adult longevity, and iteroparity (repeated reproductive events) with low reproductive success per reproductive event. Females, and presumably also males, in more northern populations mature later at 15–20 years and at a larger size than in more southern populations about 12 years. Lifespan in the wild is poorly known, but long-term mark-recapture data from Algonquin Park in Ontario, Canada suggest a maximum age over 100 years.

C. serpentina has a rugged, muscular build with ridged carapaces (though ridges tend to be more pronounced in younger individuals). 

The carapace (upper shell) length in adulthood may be nearly 50 cm (20 in), though 25–47 cm (9.8–18.5 in), is more common. C. serpentina usually weighs 4.5–16 kg (9.9–35.3 lb). Per one study, breeding common snapping turtles were found to average 28.5 cm (11.2 in) in carapace length, 22.5 cm (8.9 in) in plastron length and weigh about 6 kg (13 lb). Males are larger than females, with almost all animals weighing in excess of 10 kg (22 lb) being male and quite old, as the species continues to grow throughout life. 

Any specimen above the aforementioned weights are exceptional, but the heaviest wild specimen caught reportedly weighed 34 kg (75 lb). Snapping turtles kept in captivity can be quite overweight due to overfeeding and have weighed as much as 39 kg (86 lb). In the northern part of its range, the common snappCommon habitats are shallow ponds or streams. Some may inhabit brackish environments, such as estuaries. 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). Snapping turtles consume both plant and animal matter, and are important aquatic scavengers, but they are also 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. In some areas, adult snapping turtles can be incidentally detrimental to breeding waterfowl, as they will occasionally take ducklings and goslings but their effect on such prey is frequently exaggerated. ing turtle is often the heaviest native freshwater turtle.