A closeup of an older adult Western Cottonmouth Water Moccasin (Agkistrodon piscivorus leucostoma). As Western Cottonmouths get older their coloration becomes darker, like this one. They are also known as: Cottonmouth, Water Moccasin, Black Moccasin, Blunt-tail Moccasin, Stump-tail Water Moccasin, Viper, Cotton-mouthed Snake, Congo Snake, Trap-jaw, or Gapper.
