Cottonmouth: Snake With Potent Venom and Catlike Eyes

The cottonmouth (Agkistrodon piscivorus) is the only venomous water snake in North America, and one of only four venomous snakes in the United States. The others include the rattlesnake, copperhead and coral snake.

Populating most of the Southeast, the cottonmouth gets its name from the white color inside its mouth, although a Native American legend on how the snake got its name and venom is more lyrical.

The cottonmouth also goes by such colloquial monikers as black moccasin, gaper, mangrove rattle and several others, including "water mamba."

The cottonmouth, like the rattlesnake and copperhead are "pit vipers," using its heat-sensitive organs on each side of its head to detect its dinner. While cottonmouths have a bad reputation of being aggressive, Jeff Beane, a herpetologist at the North Carolina Museum of Natural Sciences, says that with its triangular head and steely eyes, cottonmouths will only bite when threatened.

Although Beane has studied the reptiles for years, he has no idea where its "water moccasin" nickname came from. It's possible that it originates from the belief that cottonmouths glide through underbrush as silently as someone whose feet are sheathed in moccasins.

Still, you'll know a cottonmouth when you see one. The water snakes are big, ranging from 2 to 4 feet (0.6 to 1.2 meters). Their heads are massive triangles with dark crossbands near each nostril. Their snouts are pale. Because of their venom glands, the cottonmouth has a large jowl.

The venomous snakes also come in a variety of colors. Some are downright cool to look at, their large bodies tattooed with large crossbands with hues of yellow, black and brown.

The tip of a juvenile's tale is often yellow, which the venomous snake uses as a lure to attract prey, while older adults are completely black or brown.

Taxonomists had once split the cottonmouth moccasin species into two subspecies known as the western cottonmouth and the eastern cottonmouth, with the eastern cottonmouth occupying the east coast and western cottonmouths moving into Alabama, Texas and the Gulf of Mexico region.

However, genetic testing has shown both western and eastern cottonmouth varieties are a single species. Another currently recognized subspecies is the Florida cottonmouth, which lives in a relatively small region of northern Florida and southern Georgia's swamps.

The habitat of Florida cottonmouths also overlaps with the more populous water moccasin species. Another unique variety is the northern cottonmouth which can be found in the Ozark region surrounding the Missouri River.

If you live in the Southeast, especially in Florida all the way through to southern eastern Virginia, then you have probably seen a cottonmouth. They inhabit nearly all freshwater habitats, including cypress swamps, river floodplains and wetlands.

Cottonmouth snakes tend to inhabit the same kinds of environments as nonvenomous water snakes, so caution should be taken when spotting any kind of slithering reptile out in the swamps.

You can see them during the day and at night when they hunt for their food. They might be lounging on a rock by the water's edge, hanging near a tree branch or in a pool of mud.

The cottonmouth tends to eat fish but will dine on anything it can get into its large mouth, including lizards, other snakes and turtles, baby alligators and birds. The snake is also a prolific breeder, with each litter containing one to 20 babies.

Cottonmouth snakes are ovoviviparous, which is a fancy way of saying their eggs incubate inside the mother's body; the tiny tots are live born. Once they slither out, the juvenile cottonmouths are left on their own. Mom wants nothing to do with them.

While cottonmouths are common, just because you see a snake in the water doesn't mean it's a cottonmouth. To tell them apart, stare into their eyes. If a snake has round pupils, it is not a cottonmouth. But if the eyes look like they should be on a cat, you should leave the snake alone. It's a bonafide cottonmouth.

Cottonmouth Venom Symptoms

The venom of the cottonmouth is highly toxic and can kill you, although fatalities are rare. Beane says the venom prevents the blood of humans from clotting. As the hemotoxins spread, they break down blood cells causing hemorrhaging.

The venom can lead to tissue and muscle damage, internal bleeding and lots of pain around the bite mark. Thankfully, there is an antivenin. If you are bitten, seek immediate medical attention, as is recommended with any snake bite.