A larger snake, ordinarily about 3 ft., sometimes 4 ft. long. Stout body, head shaped like that of the copperhead and similarly distinct from the neck. Back brown, reddish, or olive, with 11 to 15 rather inconspicuous bars, or pairs of bars, of dark brown, with light centers on each flank. Tail short, pointed, and dark brown or banded. Belly brownish-yellow mottled with dark blotches.

Habitat, North Carolina southward to the Gulf, westward through Kentucky, southern Illinois, and Missouri, to Oklahoma and eastern Texas.

Not so poisonous as the larger kinds of rattlesnakes, but still dangerous to human life. Quite numerous in the southern states. More aggressive than the rattlesnake, striking at everything within reach; but usually rather deliberate about striking, first opening its mouth widely for some seconds, as if to intimidate, and showing the white interior (hence the name "cottonmouth"). Usually found near wrater, and often on low limbs overhanging the water.

Only one species. The other so-called "moccasins" are either the copperhead or harmless snakes.