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 turtles are the only Macrochelys 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 a ridged carapace (upper shell), although ridges tend to be more pronounced in younger individuals. The carapace length in adulthood may be nearly 20 in, though 9.8–18.5", is more common. C. serpentina usually weighs 9.9–35.3 lb. Per one study, breeding common snapping turtles were found to average 11.2" in carapace length, 8.9" in plastron length and weigh about 13 lb. Males are larger than females, with almost all animals weighing in excess of 22 lb being male and quite old, as the species continues to grow throughout life. Any specimen above the aforementioned weights is exceptional, but the heaviest wild specimen caught reportedly weighed 75 lb. Snapping turtles kept in captivity can be quite overweight due to overfeeding and have weighed as much as 86 lb. In the northern part of its range, the common snapping turtle is often the heaviest native freshwater turtle.