The cottonmouth, also known as the water moccasin, is the only venomous water snake in North America. When alarmed, the cottonmouth hisses and shows the cotton-white color inside its mouth. That's enough to scare even the most ferocious predators away. Close-up photographs of cottonmouths in the wild give readers the opportunity to learn all about these deadly creatures--from their lethal venom to their natural hunting abilities.