The cottonmouth snake (Agkistrodon piscivorus), also known as water moccasin is a venomous semiaquatic snake that belongs to the group of pit vipers.
The generic name – Agkistrodon piscivorus – is derived from the Greek words ancistro (hooked) and odon (tooth), and the specific name comes from the Latin piscis (fish) and voro (to eat); thus, the scientific name translates into “hooked-tooth fish-eater”.
Water moccasins live in the Southeastern United States. They are found in found in Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Texas, and Virginia.
Though they can be found in fields, water moccasins usually reside in, along or near bodies of water. These snakes prefer streams, ponds, swamps, marshes and drainage ditches.
The lifespan of a water moccasin in the wild is about 15-20 years. The oldest water moccasin lived to 24.5 years old in captivity.
Water moccasins typically range from 60 to 120 centimeters (24 to 47 inches) in length; females are typically smaller than males.
Occasionally, individuals may exceed 180 centimeters (71 inches) in length, especially in the eastern part of the range.
The water moccasin has a distinctively triangular and blocky head. Pits are visible between the eyes and nostrils, and the pupils in a water moccasin’s eyes have a cat-like, elliptical shape. Their necks are thin, and they have thick, muscular bodies.
Water moccasins are covered in keeled, or ridged, scales.
Their coloration is highly variable: they can be beautifully marked with dark crossbands on a brown and yellow ground color or completely brown or black. Older adults are often dark and solid-colored whereas the juveniles are brightly patterned with a sulphur yellow tail tip that they wiggle to attract prey. The belly typically has dark and brownish-yellow blotches with the underside of the tail being black.
Cottonmouths can be found during the day or night, but forage primarily after dark during the hotter parts of the season.
During the winter, cottonmouths will hibernate, sometimes sharing dens with other venomous snakes. In consistently warm climates, the cottonmouth has been known to not hibernate at all.
Cottonmouths are excellent swimmers. They prefer to stay close to the water’s surface with their heads out. The snake even enters the sea. It has successfully colonized islands off both the Atlantic and Gulf coasts.
Cottonmouths use vision, touch, smell, and sound. They use their eyes to locate prey and their senses of hearing and touch to better perceive their surroundings. Their strongest sense is the sense of smell, in which they use their tongue to “taste” the air. This is used to analyze what is in the air around them.
Like all vipers cottonmouths have heat sensing organs located in pits near the eyes. The heat-sensitive pits detect the prey’s heat, and nerves transmit this information to the same area in the brain that receives optic nerve impulses. It is accurate to say the cottonmouth “sees” a heat image of its prey, and it can strike in darkness if the prey is even slightly warmer than its background.
Cottonmouth’s venom is potent. It is composed mainly of hemotoxins that break down blood cells, preventing the blood from clotting or coagulating.
Cottonmouths catch their food by striking, biting, and releasing venom into the prey. They also hold the prey in their coils until it is no longer struggling. Cottonmouths then open their mouths wider than the normal size by detaching the jaw bones, making it easier to swallow the prey.
Cottonmouths are opportunistic feeders and are known to consume a variety of aquatic and terrestrial prey, including amphibians, lizards, snakes (including smaller cottonmouths), small turtles, baby alligators, mammals, birds, and especially fish.
Cottonmouths may breed year-round but most matings occur between April and May.
Male cottonmouths perform a combat dance in which they slither back and forth while waving their tails to lure a female away from competing males. Males also fight each other; the winner of those battles has the right to mate with the female they were competing over. Cottonmouths breed seasonally and are believed to be monogamous.
Cottonmouths are ovoviviparous. This means they give birth to live young after developing and retaining the eggs inside their bodies.
After a gestation period of 5 months females give birth to an average of 5 to 9 live young, but can have as many as 20.
Cottonmouths are not an endangered or threatened species and populations seems to be stable throughout their range.
Cottonmouths use a gland to spray a foul-smelling musk up to 1.5 meters (5 feet) away to warn potential predators.
There are three subspecies of cottonmouth snakes: western, eastern and Florida cottonmouths.
The name “cottonmouth” comes from the white color inside the snake’s mouth.
Other common names include swamp moccasin, black moccasin, gapper, or simply viper.
The water moccasin is the only venomous water snake in North America.
Water moccasins have rather intimidating public images. Many people think of them as being ferocious animals. While they can definitely exhibit aggressive behavior, they usually don’t bite unless they feel directly bothered.
When threatened, water moccasins will open their mouths wide as a warning, a defensive behavior also displayed by non-poisonous water snakes.
As a venomous snake, cottonmouths have the ability to bite, poison, and potentially kill humans.