12 Animals That Hibernate and Survive Winter by Resting

This polar bear will go into a deep hibernation to conserve energy over a long period of time. Other animals have dormant periods that look a little different. Johnny Johnson / Getty Images

When temperatures drop and food becomes scarce, many animal species have a built-in survival trick: hibernation.

Instead of braving the elements, animals that hibernate can enter a state of deep sleep, where their body temperature drops and they conserve energy for months at a time. This adaptation helps them survive cold temperatures and ensures they have enough body weight to make it through winter.

But not all hibernating animals experience hibernation the same way. Some animals, like reptiles and amphibians, enter brumation, a sluggish, low-energy state, while others go into torpor, a short-term version of hibernation.

4 Animals That Go Into Hibernation

Many different animals hibernate to conserve energy and survive harsh conditions.

1. Bears

Bears hibernate in dens throughout the winter, drastically lowering their metabolism to conserve energy. Unlike other hibernators, they can wake up easily if disturbed and even give birth during hibernation.

2. Arctic Ground Squirrels

Hibernating arctic ground squirre — Arctic ground squirrel.
Darrell Gulin / Getty Images

These little rodents are the only known animal whose body temperature drops below freezing during hibernation. Somehow they can dramatically lower their temperatures without freezing solid.

3. Big Brown Bats

Big brown bats hibernate in caves, attics and tree cavities, slowing their heart rate to just a few beats per minute. They rely on stored fat to make it through the cold months.

4. Wood Frogs

These amphibians actually freeze solid! Their hearts stop, their body temperature drops to match the environment and they survive on glucose antifreeze until spring.

4 Animals That Go Into Brumation

Brumation is a version of hibernation that cold-blooded animals use to survive the winter. Since they can’t generate their own body heat, they rely on external temperatures to regulate their activity. During brumation, these animals slow down significantly but wake up occasionally for water.

1. Turtles

Turtles burrow into the mud at the bottom of ponds and lakes, absorbing oxygen through their skin while in brumation. Some species can survive months without surfacing for air.

2. Snakes

Many snake species, like garter snakes, gather in large dens and enter brumation together. They remain still and conserve energy until warmer temperatures return.

3. Alligators

Alligators enter brumation in shallow water or mud, slowing their metabolism to near dormancy. They can survive freezing temperatures by sticking their snouts above the ice to breathe.

4. Lizards

Different lizard species, such as bearded dragons, brumate by slowing their activity and food intake. They remain mostly inactive until their environment warms up again.

4 Animals That Go Into Torpor

Torpor is a short-term, daily or weekly state of dormancy that helps animals survive brief periods of cold or food scarcity. Unlike full hibernation, animals in torpor can wake up quickly when conditions improve.

1. Hummingbirds

Hummingbirds enter torpor overnight to conserve energy, reducing their metabolic rate and body temperature dramatically. This helps them survive cold nights when food is unavailable.

2. Little Brown Bats

Some bat species, such as the little brown bat, use torpor on a nightly basis to save energy. Unlike true hibernation, they can quickly become active when needed.

3. Mice

Mice enter torpor in response to extreme cold or lack of food, slowing their metabolism for a few hours or days. This temporary, energy-saving state helps them survive until conditions improve.

4. Skunks

Skunks don’t fully hibernate, but they do enter torpor during particularly harsh winter weather. They stay in dens and sleep for extended periods while occasionally waking to forage.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.