: a venomous semiaquatic pit viper (Agkistrodon piscivorus) of the southern United States closely related to the copperhead—called also cottonmouth, cottonmouth moccasin
Illustration of WATER MOCCASIN
Either of two species of pit viper that inhabits marshy lowlands of the southeastern U.S. and Mexico. The U.S. species (Agkistrodon piscivorus) is called a cottonmouth because it threatens with the mouth open, showing the white interior. It is up to 5 ft (1.5 m) long and is completely black or brown with darker crossbands. A dangerous snake with a potentially lethal bite, it tends to stand its ground or move slowly away when alarmed. It will eat almost any small animal, including turtles, fishes, and birds. See alsocopperhead.