Photo Credit: Roger Birkhead
Photo Credit: Carrie Threadgill
SCIENTIFIC NAME: Agkistrodon piscivorus
OTHER NAMES: Cottonmouth, Water Moccasin, Moccasin.
STATUS: Common statewide. Occurs in most aquatic habitats, but reaches greatest abundance in Coastal Plain swamps. The only venomous aquatic snake in North America. Includes subspecies A.p. piscivorus (eastern cottonmouth), A.p. conanti (Florida cottonmouth), and A.p. leucostoma (western cottonmouth). Lowest Conservation Concern.
DESCRIPTION: Eastern cottonmouth (Agkistrodon piscivorus) are large, aquatic, venomous snakes. They are generally dark above – olive, brown, or black. A lighter to darker cross-banding pattern may be seen, especially on the sides. Adult snakes usually vary in length from 30 to 48 inches up to a maximum of 74 inches. Juveniles are brightly-colored with reddish-brown cross-bands and have a sulfur-colored tail. The reddish-brown cross-bands contain many dark spots and speckles but darken with age so adults retain only a hint of the former banding or are a uniform black. The scales are keeled. The eye is camouflaged by a broad, dark, facial strip. The head is thick and distinctly broader than the neck and, when viewed from above, the eyes cannot be seen. large plate like scales cover the top of the head and in front of the eyes. Eye pupils are vertical. There are pit-like depressions between the nostrils and the eyes. Anal plate is single and scales under the tail are in single rows. Cottonmouths vibrate their tails when excited. A thoroughly aroused cottonmouth throws its head upward and backward and holds its mouth wide open, revealing a white interior – the origin of the name cottonmouth.
DISTRIBUTION: Agkistrodon piscivorus is found in the southeastern states of Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, Virginia, and east Texas. There are three subspecies: the eastern, Florida, and western cottonmouths.
HABITAT: Any wetlands or waterways within their range. They inhabit brackish waters and are commonly found in swamps, streams, springs, ponds, sloughs, reservoirs, marshes, and road side drainage ditches. The cottonmouth commonly suns itself on branches, logs, or stones at the water’s edge. It will sometime wander away from its normal habitat in search of food.
FEEDING HABITS: The eastern cottonmouth eats both warm and cold-blooded prey that includes other snakes, fish, frogs, salamanders, lizards, small turtles, baby alligators, birds, mice, and other small mammals. Prey such as frogs, fish, and other snakes are held in the jaws for a few minutes after capture to allow them to succumb to the venom. Mammals are struck and then instantly released. If the prey flees before the venom takes effect, the cottonmouth tracks it by scent. Once the prey is dead, the cottonmouth swallows it head first.
Juvenile cottonmouths have a bright, sulfur-colored tail which they hold erect and wiggle like a caterpillar to attract prey within striking range.
LIFE HISTORY AND ECOLOGY: The cottonmouth is oviparous, meaning the eggs develop within the maternal body without any additional nourishment from the parent and hatch within the parent or immediately after laying. Breeding takes place during the spring. The gestation period usually lasts from three to four months. The female produces a litter of up to 12 living young. Each young is brightly patterned with a yellow tail and is relatively large – about eight to ten inches long and three-fourths inch in diameter.
The bite of the cottonmouth is highly dangerous and may be fatal. The venom of the cottonmouth is hemotoxic. The venom breaks down and destroys blood cells and other tissues and reduces the ability of blood to coagulate or clot.
Conant, Roger. 1975. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. Houghton Mifflin Co., Boston, MA. 228-229 pp.
Jackson, Jeffrey J. 1983. Snakes of the Southeastern United States. The Cooperative Extension Service, The University of Georgia College of Agriculture, Athens, Georgia. 105 PP.
AUTHOR: Kenneth Johnson, Wildlife Biologist, Division of Wildlife and Freshwater Fisheries