From the Minnesota DNR: The common snapping turtle is Minnesota's largest turtle. As an adult, its upper shell (carapace) averages (8-14 in.) in length and its weight ranges from 10-35 lbs. The largest known Minnesota individual weighed 29.5 kg (65 lbs.) and had a carapace that was 49.5 cm (19.5 in.) long. The common snapping turtle's carapace is variably colored from green to brown to black, and often has moss covering it. In young turtles, raised crests form three longitudinal keels along the carapace. These crests gradually disappear as the turtles mature. The back edge of the carapace in all sized turtles is strongly toothed. The lower shell (plastron) is considerably reduced in size relative to the upper shell, and provides little protection for the turtle. Common snapping turtles have a long tail with a series of raised scales along the top that create sawtooth projections. Their head is large, with large, powerful jaws, and their neck is long. The common snapping turtle is usually docile in the water, but can be aggressive when it is on land, often lunging forward and striking out to "snap" at its foe.