Man from Evangeline Louisiana lets cotton mouth snakes bite him over 10 times.North America’s only poisonous water snake, the water moccasin has adistinctive blocky triangular head, thick body and a dangerous bite.They rarely bite humans, however, and only attack when threatened. Theyare semi-aquatic, happy both swimming in water and basking on land intheir native range of the Southeastern United States. Water moccasin isa colloquial name for Cottonmouth snakes.