Do Cottonmouth Snakes Go Away in the Winter?

Written by Gail Baker Nelson
Updated: January 23, 2023
© KF2017/
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If you noticed that snakes seem absent during the winter, you probably know that they’re tucked into their dens until the spring. For people who fear snakes, it’s nice to know when the likelihood of seeing any snake, let alone a venomous one, is lower. But do cottonmouths go away in the winter, and if so where? Let’s find out!

What is a Cottonmouth Snake?

Cottonmouth Snake
Cottonmouths are named for the white lining inside their mouth which resembles cotton.

©Marcum Havens/

This misunderstood yet highly venomous snake species is the only semi-aquatic pitviper in North America. Contrary to the popular myth, they can bite underwater. After all, their favorite foods are fish and frogs, and I haven’t seen many fish walking on land.

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Cottonmouth snakes are among the most prevalent venomous snakes in the southern United States. You can find them from central Texas east to Florida and as far north as southern Illinois. Three subspecies of these semi-aquatic snakes have similar habitat preferences but slight variations in their color or markings. These snakes prefer marshy, wet habitats where they can easily grab a meal. They are pitvipers in the same genus as copperheads and have a unique threat display that gives them their common name: They coil up and show their fangs and the cotton-white inside of their mouth.

Depending on whom you ask, they’re either respected or feared because they’re highly venomous and tend to stand their ground instead of high-tailing it when they’re threatened. Some people say they’ll even chase you, but most herpetologists and herpetoculturists say that this is a myth. The more likely explanation is that the person being “chased” was standing between the snake and a water source where the cottonmouth feels safest. Like other snakes, they’re cold-blooded and depend on the sun’s heat to support their body’s processes and maintain their core body temperature.

When are you most Likely to See a Cottonmouth?

Cottonmouths are considered to be one of the few semi-aquatics snakes in the world.
You are more likely to see cottonmouths during the spring and the fall.

©jo Crebbin/

Their normal behavior generally limits the time you’ll most likely see one. Although they do sometimes hunt actively, these ambush predators don’t move around much unless they’re heading from one hiding spot to another or in the water hunting for fish. During the spring and fall, they’re either heading to or from brumation spots like abandoned burrows and hollow trees or looking to mate.

Even though they’re nocturnal, cottonmouths are sometimes found during the day during cooler spring and fall temperatures. They typically shift to their preferred nocturnal habits when the summer heats up.

When winter rolls around, cottonmouths begin looking for a cozy spot to pass the winter. They’ll stay there and brumate from about November to March in most of their range. However, that may be different in southern Florida because it may only get cold enough to cause them to brumate every few years or so. As a result, you may see them all year long in the southern tip of Florida and a few of the islands.

What is Brumation?

Brumation is the reptilian equivalent of hibernation. Snakes living in habitats where the temperatures routinely fall below their tolerance for cold must brumate to keep from becoming sick or dying. During the late summer, they eat more and try to fatten up a bit for the winter.

Like other snakes, cottonmouths can’t eat but still need to drink during brumation. Additionally, the snakes may come out on days that get a little warmer before tucking back into their cozy winter spot. In some areas, snakes may only brumate for a couple of months, if at all. Yet, the weather in other areas may keep the snakes tucked into their winter home for several months.

While all species have different tolerance levels for the cold, North American snakes like the cottonmouth generally start looking for winter shelter when daytime temperatures drop below 60 degrees Fahrenheit. For many species, the length of daylight is also a factor in what triggers this cycle.

Where do Cottonmouths Go During the Winter?

Moccasin Snake
Cottonmouths spend the winter in hollow logs or underneath leaves.

©Nathan A Shepard/

Most snakes brumate for a little while during the cooler months. Cottonmouth snakes are no exception and brumate for at least a couple of months throughout most of their range. The only place they may stay active year-round is near the southern tip of Florida, along the coasts, and on a few islands.

This species is not overly picky and will tuck itself into hollow logs or piles of wet leaves and brush near a water source. Cottonmouths are not social and typically brumate alone. This antisocial behavior is probably good because they can be cannibalistic, eating smaller individuals of the same species.

If you happen to find a cottonmouth tucked into its den during the winter, leave it alone, if possible. Even if it’s cold out, the snake can still bite and send you to the hospital.

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The Featured Image

Side view of a Cottonmouth snake, ready to strike. The snake has a large spade-shaped head.
Side view of a Cottonmouth snake, ready to strike. The snake has a large spade-shaped head.
© KF2017/

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About the Author

Gail’s love for a very misunderstood group of animals, reptiles, led her to write about and draw them. She loves the natural world and it’s endless inspiration for her work. She is a freelance writer and illustrator, and her latest book, “Pebble Skins and Fast Walkers: What’s In a Name?” Is due out in early 2023.

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  1. Cottonmouth | Seaworld, Available here:
  2. Florida Cottonmouth | Reptarium Reptile Database, Available here:
  3. Northern Cottonmouth | Reptarium Reptile Database, Available here: