Last updated on April 19, 2014 at 8:45 EDT

Cottonmouth (Water Moccasin)

The Cottonmouth or Water Moccasin, Agkistrodon piscivorus, is a pit viper found in the United States. It is a close relative of the copperhead. The Cottonmouth is found along the eastern coast, southern, and Midwest areas of the United States. Along the coast they are found as far north as Virginia and Illinois in the interior states. They are rarely found away from permanent water sources. They also enjoy open pine forests and bald cypress swamps.

Cottonmouth snakes average in size from 20 to 48 inches long. The longest has been recorded at 74.5 inches. They are typically dark in color, either black, dark brown, or a dark olive green, with a muddy appearance. Sometimes muted banding is present. Juveniles have a more striking appearance, with distinctive light and dark banding and a bright yellow-green tail tip. As they age, the banding and color on the tail tip fade.

Within their range, cottonmouths have a reputation as being aggressive snakes. However in test done to measure their behavioral responses, half of the subjects tried to escape and more than three quarters of them used threat displays or other defensive tactics. Many of the snakes that did bite did not inject venom. The cottonmouth will also stand its ground and open its mouth to warn predators away. But will usually flee if left alone.

Although these snakes are heavy, they are capable of climbing low branches and will sometimes be seen sunning themselves on branches overhanging the water. They are semi-aquatic and spend most of their time in or around the water. When swimming, they skim along the surface. This distinguishes them from other water snakes that tend to swim below the surface.

They take a wide variety of prey including fish, small mammals, lizards, birds, small turtles, baby alligators, and even other snakes. Usually a victim is envenomed quickly with a bite and then released. If it does not succumb immediately, it is tracked by scent. Like all pit vipers, the cottonmouth has pits on the sides of its nose that sense body-heat of warm blooded animals in the form of infrared light, thus its hunting ability is not impaired at night.

The cottonmouth breeds in the spring and fall and is ovoviviparous, giving birth to 10 or so live young after a 3 month gestation period. The young average around 20 cm in length. There is little to no maternal care. Juvenile cottonmouths use the bright color on the tip of their tail as a lure to entice prey items to approach within striking range. As they mature, this tail color fades along with the associated behavior.

Cottonmouth Water Moccasin