pond turtle, any of several freshwater turtles of the families Emydidae and Bataguridae. Two of the best known are emydids: the Pacific, or western, pond turtle (Clemmys marmorata) and the European pond turtle (Emys orbicularis).
The Pacific pond turtle is one of the few turtles native to western coastal North America. Found from southern Canada to southern California, it usually inhabits ponds and other quiet waters. It once was widely sold for food in California. The smooth, broad upper shell of the Pacific pond turtle is about 15–25 cm (6–10 inches) long and is brown or blackish with yellow spots and streaks. The lower shell is yellow and black. The Pacific pond turtle is a highly aquatic, wary reptile. It feeds on plant and animal material and basks in the sun.
The European pond turtle, also known as the swamp turtle, or swamp tortoise, is found from the Ural Mountains through Europe and in northwestern Africa. It is primarily aquatic and omnivorous. The upper shell, which reaches a length of about 12–13 cm (5 inches), is brownish or blackish with yellow speckling and sometimes resembles that of the Pacific pond turtle. Unlike the latter species, the European pond turtle has a hinged plastron, although it is usually unable to close its shell completely.