Agkistrodon piscivorous leucostoma
Up to 74 inches
North America; statewide in Louisiana
Any aquatic area both permanent and temporary
Wild - Mostly fish but will eat virtually any vertebrate prey small enough to swallow.
Zoo - Mice and rats
Long, heavy-bodied, dark brown or black; pattern of broad dark crossbands, belly brown; dark brown line from the eye to the angle of the jaw; a deep pit in the side of the head between the eye and the nostril; anal plate undivided.
Potent venom; large and ill-tempered; will coil tightly and expose white lining of the mouth to scare away intruders.
5 - 20 live young usually born during August. Young are strikingly marked but colors fade as snakes mature. Young are born with lime green tails used to lure prey.
Many water snakes are mistaken for the cottonmouth, because they will react aggressively and look similar.
"The Amphibians and Reptiles of Louisiana," Harold A. Dundee and Douglas A. Rossman