The Cottonmouth is a species of venomous water snake located in South America. Common names include variants of moccasin, swamp, moccasin, black moccasin, cottonmouth, and simply viper. Water moccasins can be up to 6 ft (2m) long and have distinctive white coloring inside the mouth, pit-like depressions behind the nostrils, a triangular head with slit-shaped pupils and fangs, and a single row of plates or scales on the undersurface of the snake, including the tail.