Cottonmouth facts for kids

The cottonmouth, also known as the water moccasin, is a type of venomous snake found in the southeastern United States. It's the only semi-aquatic (meaning it lives partly in water) viper in the world. Cottonmouths are large snakes that can deliver a painful bite if they feel threatened. When scared, they often coil up and open their mouths wide to show the bright white inside, which is how they got the name "cottonmouth." They live near water, like slow-moving lakes, streams, and swamps. They are good swimmers and can even be seen in the ocean, but they are not true sea snakes.

The scientific name for the cottonmouth is Agkistrodon piscivorus. The first part, Agkistrodon, comes from Greek words meaning "fish-hook" and "tooth." The second part, piscivorus, comes from Latin words meaning "fish" and "devour." So, its scientific name means "hook-toothed fish-eater"!

What Does a Cottonmouth Look Like?

An adult Florida cottonmouth at the Cincinnati Zoo.

The cottonmouth is the biggest snake in its group, Agkistrodon. Adult snakes are usually about 80 centimeters (31 inches) long, but some can grow much larger, even over 180 centimeters (70 inches)! Females are usually smaller than males.

Most cottonmouths are almost completely black, but their colors can vary. They might be brown, gray, tan, or olive-yellow. They have dark bands across their bodies, which can be hard to see on older, darker snakes. The belly is usually white or yellowish with dark spots.

Young cottonmouths have a more colorful pattern with dark bands on a lighter background, like tan or reddish-brown. Their tail tips are usually yellow or greenish. Young snakes wiggle their bright tail tips to trick small animals, like frogs and lizards, into coming closer so they can catch them.

It's easy to confuse cottonmouths with other snakes, especially the copperhead or harmless water snakes. Cottonmouths have broad, dark stripes on the sides of their heads behind their eyes. Water snakes look similar, but they have round pupils (the black part of their eye) and don't have the special heat-sensing pits that cottonmouths do. Cottonmouths also tend to hold their heads at a 45-degree angle when swimming.

Where Do Cottonmouths Live?

Geographic range of the cottonmouth in the United States.

Cottonmouths live in the eastern and southeastern parts of the United States. You can find them from southern Virginia all the way down to Florida, and west to Arkansas, Oklahoma, and Texas. They are also found in states like Alabama, Georgia, Illinois, Indiana, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, and Tennessee.

They prefer to live near water, such as swamps, marshes, creeks, and the edges of ponds and lakes. They can even live in slightly salty water, like near the coast. However, they can also be found away from water in places like pine forests or sandy areas.

Are Cottonmouths Endangered?

No, the cottonmouth is not considered an endangered species. It's listed as "least concern" by the IUCN Red List, which means there are still many of them around. However, in some specific areas, like Indiana, they are listed as an endangered species because their wetland homes are being destroyed.

How Do Cottonmouths Behave?

A cottonmouth showing its "cottonmouth" threat display.

When cottonmouths feel threatened, they often try to escape. But if they can't, they will stand their ground and put on a show! They might vibrate their tail and throw their head back, opening their mouth wide to show the bright white inside. This is where the name "cottonmouth" comes from. They might also hiss loudly. If something touches their mouth, they snap their jaws shut, which is why some people call them "trap jaw." They can also release a strong, smelly musk from glands near their tail to scare off predators.

Unlike harmless water snakes, which usually swim away quickly, cottonmouths often stay put and perform their threat display. Cottonmouths are active both during the day and at night. On sunny days, they might be found resting in the shade. In the morning or on cooler days, they like to bask in the sun to warm up. At night, they are often very active, swimming or crawling around. Yes, they can bite even when they are underwater!

In colder areas, cottonmouths hibernate during the winter. In warmer places, they might only hibernate for a short time or not at all.

What Do Cottonmouths Eat?

A light-colored adult cottonmouth.

Cottonmouths are meat-eaters. They mostly eat fish and frogs, but they will eat almost any small animal they can catch. This includes small mammals, birds, other snakes, small turtles, and even baby alligators! Sometimes, they even eat other cottonmouths. Young snakes use their bright yellow or green tail tips to wiggle and attract prey, like frogs and lizards.

They are smart hunters. They might corner fish in shallow water or under logs. They also take advantage when water dries up, eating the fish and tadpoles that become trapped. They are also one of the few snakes that will eat dead animals (carrion).

Who Eats Cottonmouths?

Cottonmouths have several predators. These include snapping turtles, falcons, American alligators, horned owls, eagles, and large wading birds like herons and egrets. Other snakes that eat snakes, like kingsnakes, might also prey on them. However, cottonmouths have a special defense against snake-eating predators: they can raise a loop of their body and throw it at the attacker to scare them away.

How Do Cottonmouths Reproduce?

Cottonmouths give birth to live young, usually between one and 16 babies at a time, but sometimes up to 20. Litters of six to eight babies are most common. Newborn cottonmouths are about 22–35 centimeters (8.5–14 inches) long. If there's plenty of food and good weather, females can start having babies when they are less than three years old. The young are usually born in August or September.

Interestingly, female cottonmouths can sometimes reproduce without a male partner. This is called facultative parthenogenesis, which means they can switch from regular reproduction to an asexual (without a partner) way of having babies.

Cottonmouth Venom

A newborn cottonmouth, showing its bright markings and yellow tail tip.

Cottonmouth venom is strong and can damage tissue. While a bite can be painful and cause swelling, deaths from cottonmouth bites are very rare. The venom does not usually affect the whole body or the nervous system. If someone is bitten, they can be treated with a special medicine called CroFab antivenom.

Bites from cottonmouths happen often in some areas, but it's important to know that these snakes are not usually aggressive. They prefer to escape or warn you with their threat display before biting. Many people have encountered these snakes without ever being bitten.

Types of Cottonmouths

There are three recognized types (subspecies) of cottonmouths:

Images for kids

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  Geographic distribution of the two species of cottonmouth, Agkistrodon piscivorus and Agkistrodon conanti

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  A cottonmouth in water in Tennessee—the high position in the water and upward-tilted head can help distinguish it from Nerodia watersnakes such as the common watersnake, although there is substantial similarity.

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  A common watersnake (Nerodia sipedon) swimming—a nonvenomous species often mistaken for the cottonmouth

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  Northern cottonmouth (Agkistrodon piscivorus) eating a rodent, Bon Secour National Wildlife Refuge, Alabama (23 October 2011)

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  Juvenile cottonmouth

See also

In Spanish: Boca de algodón para niños