Water Moccasin, Cottonmouth: Different Names, Same Venomous Snake

water moccasin
The cottonmouth (Agkistrodon piscivorus), also known as the water moccasin, is identifiable by, and named for, the whiteness of the inside of its mouth. Pixabay

When Hurricane Florence blew through the Carolinas in September 2018, wind, rain, and flooding were not the only threats people faced. A bevy of slithering, sneaky, watch-where-you-step snakes came out of hiding. Chief among them was the notorious and venomous cottonmouth, a.k.a., water moccasin, that turned up in the floodwaters, scaring the bejesus out of many people.

Yet, Bradley Thomas Dixon, a volunteer firefighter, was not scared when he came across two cottonmouths in the storm's aftermath. In fact, he seemed mesmerized as he took a video of two water moccasins casually sunning themselves in a pool of mud near Topsail Island, North Carolina. "These little cottonmouths are sitting here soaking up some sun," Dixon casually narrated as he focused his smartphone. "There's two of them, a big one and little one. The big one looks to be about 4 feet long, the little one's about 3-and-a-half feet long."


Thank goodness Dixon didn't try to touch them. 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 is a "pit viper," 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 nickname — water moccasin — 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.


What Does a Cottonmouth Look Like?

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

The 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 snake uses as a lure to attract its dinner, while older adults are completely black or brown.


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. 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, or hanging near a tree branch, or as our firefighter Bradley Dixon found out, in a pool of mud.

What Do Cottonmouths Eat?

The cottonmouth dines on anything it can get into its large mouth, including lizards, smaller snakes and turtles, baby alligators, birds and fish. The snake is also a prolific breeder, with each litter containing one to 20 baby snakes. Cottonmouths are ovoviviparous. That's a fancy way of saying its eggs incubate inside the mother's body. The tiny tots are live born. Once they slither out, the children 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 might not want to pick one up. It's a bonafide cottonmouth.


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.