Cottonmouths are the largest species of Agkistrodon vipers in the United States measuring at least 31 inches in length and weighing 10 to 20 ounces with the females being slightly smaller than the males.

Most cottonmouths have very dark coloring to totally black excluding their facial markings. Their scale patterns not only vary by region, but the juveniles also have a much brighter, contrasting design.

Cottonmouth snakes have many natural predators such as snapping turtles, falcons, alligators, different wading birds, and more. Unlike copperheads, cottonmouths tend to not flee when threatened and will expose the white interior of their mouth while vibrating its tail even though there is no rattle.

Their venom is rarely fatal to humans but can sometimes decay the tissue so much, we may require amputation. 

There are three subspecies of cottonmouth snakes native to the southeastern United States. They are the world’s only semiaquatic viper so they prefer habitats such as streams, marshes, and shallow lakes. Even though cottonmouths are strong swimmers and have even been seen swimming in the ocean, they are not considered fully marine. In fact, they can be found living in places more than a mile away from water.

Cottonmouths are carnivorous primarily eating small vertebrates such as birds, frogs, mammals, fish, snakes, and small turtles and alligators; they are also one of the few snakes that eat carrion. They will take advantage of the drier seasons when the water starts to dry up to corner fish or tadpoles. If the prey is small, cottonmouths will latch on and coil around it until it stops moving, while with larger prey, they have been seen biting on for a few seconds to inject their venom and immediately releasing in case the snake gets injured.

The mating season for cottonmouths is in the warmer parts of the year when males will fight each other for the right to mate with active females. After several months, the eggs will develop and hatch inside the mother before she gives birth to 1-16 live newborn snakes. Mothers don’t stay around too long as the young already have fangs and venom and are prepared to hunt and defend themselves.

The largest recorded cottonmouth was found in Virginia reaching over 70 inches!