Cottonmouth vs Bullsnake: What’s the Difference?

Written by Brandi Allred
Updated: January 24, 2023
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If you’re looking at a snake, and you’re not sure whether it’s a cottonmouth or a bullsnake, then you’ve come to the right place. Both snakes live in many of the same areas, and even eat some of the same things. But, there are a few very important differences between the cottonmouth vs the bullsnake.

Here, we’ll learn how to tell a cottonmouth from a bullsnake, and why it’s important to know the difference. Read on to learn more about what makes cottonmouths different from bullsnakes!

Comparing Cottonmouths vs Bullsnakes

Cottonmouths and bullsnakes differ in appearance, size, location, habitat, behavior, and lifespan.
CottonmouthBullsnake
Size24-48 inches36-60 inches; can reach 8 feet
AppearanceBrown, black, or gray, with a white interior of the mouthYellow with black or brown checkered pattern
Location and HabitatSoutheastern United States; swamps, rivers, wetlandsEastern half of the United States and southern Canada; fields and prairies
BehaviorWill stand its ground if threatenedDoes not hesitate to bite if threatened
LifespanUp to 10 years12 years in the wild; up to 30 years in captivity

The Key Differences Between Cottonmouths vs Bullsnakes

Florida Cottonmouth or water moccasin snake, close up

©iStock.com/Saddako

The key differences between cottonmouths and bullsnakes are appearance, size, location, habitat, behavior, and lifespan.

Let’s explore these differences in detail!

Cottonmouth vs Bullsnake: Appearance

Closeup of a bullsnake in the wild. The bullsnake has a shield on its nose to help it dig.

Bullsnakes have a yellow or tan base color with an all-yellow belly.

©Greg Birkett/Shutterstock.com

Cottonmouths are best known for the cotton-white interior of their mouth, which they display when threatened. Their overall scale color varies greatly, but most individuals are a shade of brown, yellow, or gray, with irregular bands. Young cottonmouths display very clear light and dark bands of yellow and brown down their body. As they grow older, they become duskier, and their pattern becomes less clear.

Bullsnakes have a yellow or tan base color with an all-yellow belly. Their sides and backs are marked by irregular brown or black splotches arranged in a checkerboard pattern. They lack the white interior of the mouth and have narrow, python-like heads.

In contrast to the bullsnake, the cottonmouth has the hallmark triangular head of the pit viper. Not only do cottonmouths have large, retractable fangs, but they also have large venom glands just behind their eyes. Furthermore, while bullsnakes have round pupils, cottonmouths have vertically elliptical pupils.

Cottonmouth vs Bullsnake: Size 

The Bullsnake is similar to the Western Rattlesnake. It has black, brown, reddish or white dorsal blotches on a yellow, cream-colored or beige ground.

Bullsnakes grow much longer than cottonmouths.

©steve estvanik/Shutterstock.com

Cottonmouths are not light snakes. They have heavy bodies that stay afloat when swimming. They grow to a maximum length of 48 inches as adults, though adults may be anywhere from 24-48 inches long. Their heavyset bodies may seem intimidating, but they’re not used for constriction like boa constrictors and ball pythons.

Bullsnakes are similarly heavy-bodied, but grow much longer than cottonmouths. Bullsnakes can attain lengths of up to 72 inches, or, six feet. With that length, it’s not surprising that the bullsnake is one of the longest snakes in North America.

Cottonmouth vs Bullsnake: Location and Habitat

Moccasin Snake

Cottonmouths live throughout the coastal areas of the southeastern United States.

©Nathan A Shepard/Shutterstock.com

Cottonmouths live throughout the coastal areas of the southeastern United States. They can be found as far north as southern Virginia, and as far south as the Florida Panhandle. Their range extends as far west as Texas.

Bullsnakes occupy the entire eastern half of the United States. Their range extends as far north as southern Canada and northern Mexico, though they’re not generally found in the southeastern United States.

As semi-aquatic snakes, cottonmouths are almost always found near sources of fresh water, like lakes, wetlands, slow-moving rivers, and swamps. They are only occasionally found far from fresh water. Unlike other semi-aquatic snakes, like water snakes, cottonmouths don’t climb onto tree branches overhanging the water. Instead, they’re often seen sunbathing on river banks, logs, or rocks near the water.

Bullsnakes are mostly snakes of the field. They can occasionally be found in rocky outcroppings or near freshwater, but they stick mostly to grassy prairies. They’re frequently found in agricultural fields, and may even encroach on suburban areas.

Cottonmouth vs Bullsnake: Behavior

Juvenile Cottonmouth Snake swimming in a pond. They have even stronger contrasting bands of colors.

The cottonmouth has a bad reputation for aggression.

©Mark_Kostich/Shutterstock.com

Cottonmouths are notorious for their aggressive behavior towards humans. They do not slither into the water, like water snakes, or quietly slip into the bushes to hide. Instead, they coil up, open their mouths wide, and hiss. Cottonmouths won’t hesitate to bite anyone that gets too close, and with their deadly venom, it’s better not to get too close.

Bullsnakes have no venom. Instead, they rely on constricting prey to death with their powerful muscles. They may not have a venomous bite, but that doesn’t mean that they don’t know how to use their teeth. Bullsnakes are known to vigorously defend themselves, and may even bite multiple times in self-defense.

No matter the species, it’s important to remember that all snakes should be treated with respect. You should never approach or attempt to handle, or harm, a wild snake.

Cottonmouth vs Bullsnake: Lifespan

Bullsnake - Coiled

Bullsnakes may live as long as 12 years.

©iStock.com/92968526

While there is no firm answer on just how long wild snakes can live (due to a lack of data), scientists can piece together lifespans using a few sources. Observation of tagged individuals throughout their lives, as well as records of captive snakes, give scientists a good estimate of their lifespan. Cottonmouths live to about 10 years, while bullsnakes may live as long as 12 years.

The photo featured at the top of this post is © Markparker1983/Shutterstock.com

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About the Author

Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She holds degrees in English and Anthropology, and spends her free time writing horror, scifi, and fantasy stories.

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