Cottonmouth Snake: Key Facts

Did you know that cottonmouth snakes can swim on top of the water’s surface? Or that their venom can inflict serious medical complications on humans? Keep reading to learn more about these and other cottonmouth snake key facts.

Quick Facts About Cottonmouth Snakes

Scientific Name:Agkistrodon piscivorus
Type of Animal:Reptile: snake
Number of Subspecies:3
Physical Description:Large, thick-bodied pit vipers with blocky, triangular heads. Adults are black, dark brown, gray, or olive colored with faint darker patterns and light bellies; juveniles are lighter in color, their patterns more visible, and they have bright yellow tail tips. Cottonmouths get their name from the light-colored inside of their mouths, which they display when they feel threatened.
Distribution:Widely distributed throughout southeastern portions of the United States
Habitat:Primarily found in wetland regions: swamps, marshes, lakes, ponds, streams, drainage ditches, etc.
Size:Typically 2 to 4 feet long, can grow up to 6 feet; 3 to 4 pounds.
Diet:Opportunistic carnivore; foods include:
– Fish
– Amphibians
– Small mammals
– Birds
– Eggs
Lifespan:15 to 20 years on average.

What Are Cottonmouth Snakes?

Cottonmouth snakes are semi-aquatic pit vipers that can be found throughout the southeast United States, from Texas to Florida and northward to Virginia, Illinois, Indiana, and Missouri.

There are three subspecies of cottonmouth: the western, eastern, and Florida cottonmouths. Their ranges sometimes overlap and they can crossbreed with each other, and they all look very similar so they are difficult to tell apart.

Cottonmouths spend as much time in the water as they do on land; hence their common name, water moccasin. They can often be seen swimming along the surface of a body of slow moving water, and they tend to live near water sources such as ponds, marshes, creeks, and even swimming pools and drainage ditches.

Cottonmouths eat many different kinds of food, including fish, frogs, salamanders, rats, mice, small birds, and bird eggs. They are ambush predators who will attack prey animals that get too close, injecting their venom into the creature and wrapping their body around it until it dies.

Cottonmouths have between 1 and 20 live babies every two to three years. Young cottonmouths are frequently targeted by larger predators, and very few of them survive to adulthood.

Can a Cottonmouth Snake Kill You?

Cottonmouth snake venom is hemotoxic; it breaks down blood vessels and can cause such complications as internal bleeding, organ damage, and gangrene. If not treated properly, any of these conditions can lead to death.

So yes, technically, cottonmouths can kill you. Though they account for less than one percent of snake bite deaths in the U.S., the venom is extremely dangerous.

If you know or suspect you’ve been bitten by a cottonmouth, get to the hospital immediately. The sooner you get proper medical treatment, the quicker and better your recovery will be. 

To learn more about cottonmouth venom and to get an idea of how much they can inject each time they bite, check out this video:


Cottonmouths are a common sight in many of the southeastern states. These venomous pit vipers typically live in wetlands (and are sometime confused for water snakes), where they swim in the water, bask on flat rocks, and hunt for a variety of small prey animals.

Read also about other forest reptiles – here are our guides about bull snakes, copperheads, snapping turtles.

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