Cottonmouths are very dangerous snakes, and their bite can be fatal. Their distribution in the state is generally limited to permanent or semi-permanent bodies of water in the Coastal Plain. This species breeds in the spring, and their young are born alive. Coloration is variable and ranges through shades of brown, olive, and sometimes yellowish. Their average length is around four feet. When aroused, the cottonmouth's rapidly vibrating tail and gaping mouth readily distinguish it from harmless water snakes.