Terrapin, << TEHR uh pihn, >> is the common name of certain freshwater or salt-marsh turtles. Terrapins eat crabs, clams, snails, and other water animals, as well as green plants. The female, which is larger than the male, has an upper shell that measures 6 to 9 inches (15 to 23 centimeters) long. The common United States terrapins are the diamondback terrapins, of which there are several subspecies. These terrapins live along the Gulf and Atlantic coasts as far north as Massachusetts.
