Cottonmouth and Copperhead Hybrids: Can it be Done?

Written by Brandi Allred
Published: April 13, 2022
Image Credit Kristian Bell/Shutterstock.com
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Think You Know Snakes?

If you live in, or have visited, the eastern United States, then you may have heard of cottonmouth and copperhead snakes. Both are venomous, and they occupy many of the same habitats. But are there cottonmouth and copperhead hybrids?

Hybrids abound in the natural world, though not all of them can produce offspring. From the mule to the liger, hybrid creatures fascinate people. Hybrid snakes exist, and there just might be one lurking in the forests of the eastern United States. For years, reports of cottonmouth and copperhead hybrids have abounded, but is there any truth to the stories?

Here, we’ll find out just what makes a cottonmouth what it is and a copperhead what it is. Then, we’ll look at the biggest differences between the two species. After that, we’ll answer the question of whether or not cottonmouth and copperhead hybrids exist and, if so, where they might live. Finally, we’ll go over how you can tell if a snake you saw is a hybrid.

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Background: Cottonmouth (Agkistrodon piscivorus)

Cottonmouth Snake
Cottonmouths are also known as water moccasins.

Jay Ondreicka/Shutterstock.com

Cottonmouths are one of the most famous venomous snakes in the southeastern United States. They live throughout the coastal southeast (including Florida) and as far west as the Mississippi delta. It’s easy to recognize cottonmouths by their snow-white mouth interiors, which they readily display when threatened. They grow up to four feet long and have heavy bodies. Cottonmouths have a base color that is light brown to dark brown with lighter, chevron-shaped markings.

Cottonmouths eat a diet that consists almost entirely of fish and amphibians, though they won’t pass up a small mammal or reptile if given the opportunity. They’ve also been known to eat baby alligators, birds, and even small turtles. They’re capable hunters both in the water and on the land.

Background: Copperhead (Agkistrodon contortrix)

What Does a Copperhead Snake Look Like
Copperheads occupy many of the same areas as cottonmouths, with the exception of the Florida panhandle.

Breck P. Kent/Shutterstock.com

Copperheads are very similar to cottonmouths in appearance, location, and behavior. But they have an entirely different pattern of tan and light brown scales. Rather than chevron stripes, like the cottonmouth, copperhead bodies are covered in distinct, hourglass-shaped markings. 

Like cottonmouths, copperheads are venomous. They’re widespread, and their markings give them excellent camouflage. Because of these factors, they’re responsible for many bites on humans every year. However, copperhead venom is not nearly as dangerous as rattlesnake venom, and it rarely proves fatal. Bites still require immediate medical intervention, but prognoses are generally very good.

What’s the Difference Between Copperheads and Cottonmouths?

cottonmouth vs copperhead
Cottonmouths and copperheads differ in appearance and behavior.

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The biggest difference between cottonmouths and copperheads comes from their appearance. When seen side by side, it’s easy to recognize the differences in color and patterns. But if you saw one of these snakes in the bush, it might be harder to determine which is which. 

Another difference comes from each species’ behavior. Only cottonmouths coil up and display the white interiors of their mouths. Also, cottonmouths are much more likely to be seen in the water and rarely stray too far from permanent water sources. Copperheads are slightly smaller than cottonmouths, with thinner bodies.

As babies, copperhead snakes have bright green or yellow tail tips. They use these to attract prey. Cottonmouth babies don’t have brightly colored tail tips. Furthermore, copperheads are more likely to live near areas of human habitation than cottonmouths. One of the biggest threats to copperheads is vehicles; the snakes die when crossing roads and highways.

Can Copperheads Breed with Cottonmouths?

Cottomouth vs Copperhead
Cottonmouth and copperhead hybrids have only been created in captivity.

Mark_Kostich/Shutterstock.com

Cottonmouth and copperhead hybrids have only been confirmed in captivity. No wild cottonmouth-copperhead hybrids have ever been verified. Because the two species are in the same genus (Agkistrodon), interbreeding is possible. But, each species has its own set of behaviors and mating rituals, which means that hybridization in the wild is highly unlikely.

To date, no wild specimens have ever been confirmed. However, numerous breeders have successfully hybridized cottonmouths with copperheads.

What are Copperhead/Cottonmouth Hybrids Called?

Accounts vary, but most breeders call their cottonmouth-copperhead hybrids either cottonheads or coppermouths. Alternatively, they’re known simply as cottonmouth and copperhead hybrids. Due to the paucity of living specimens, it’s unknown how the hybridization affects things like venom potency, lifespan, and reproductive potential.

How Can You Tell if a Snake is a Hybrid?

Northern Copperhead (agkistrodon contortrix mokasen) on leaf litter - taken in New Jersey. Its ground color is pale brown to pinkish-brown, and it has darker, hour-glass shaped bands down its body.
Hybrid snakes get half of their genetic material from each parent.

iStock.com/David Kenny

Cottonmouth and copperhead hybrids generally have scale patterns somewhere in between the two species. They may have the hourglass shape of the copperhead combined with the chevron shapes of the cottonmouth’s pattern. Or, they may simply look like one or the other species.

The only real way to tell if a strange-looking snake is a cottonmouth-copperhead hybrid is to test its DNA.

Can Black Rat Snakes Breed with Copperheads?

Just as there are stories of cottonmouths breeding with copperheads, there are tales of copperheads breeding with an entirely different snake, the black rat snake. Black rat snakes (Pantherophis obsoletus) are non-venomous snakes that also live in the southeastern United States. Oftentimes, they share dens with copperheads during the cold winter months. But, can the two produce super venomous, hybrid offspring?

Unlike the cottonmouth and copperhead hybrids, copperhead and black rat snakes cannot breed. Black rat snakes belong to an entirely different genus than copperheads, which means they can’t produce offspring. So, even if these two species did mate, they wouldn’t be capable of reproducing.

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