Have you ever wondered why animals hibernate? Well, one big reason revolves around conserving energy. Hibernation slows down an animal’s heart rate, metabolic system, breathing, and body temperature. In winter, food can be scarce, so this process allows them to survive with very little sustenance. Another reason is that hibernation helps them survive brutally cold winter temperatures. Now, bears are one of the best-known hibernating animals, but what about the other animals that sleep through winter? Let’s discover them!

Ground Squirrel
Unlike tree squirrels, ground squirrels are all about burrowing. With their brown fur and long claws, ground squirrels look nearly identical to their arboreal-dwelling cousins. However, instead of using their claws to climb, ground squirrels use them as shovels. Dozens of ground squirrel species roam the earth — and not all hibernate. But interestingly, the ones that settle in for a long winter’s nap do so alongside friends and family.

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Chipmunk
Although chipmunks don’t truly hibernate, they do enter a state known as torpor. During the fall, they pack their cheeks with acorns and stockpile food in burrows, which are usually about 3 feet underground. When the temperatures plummet, the chipmunks retreat to their burrows and enter torpor, where their heart rate and temperature drop significantly. They do sometimes wake up to eat during the winter months, and you might occasionally see them outside. However, once springtime sweeps in, chipmunks fully wake up and immediately become active again.

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Wood Frog
Wood frogs are the most northern-dwelling amphibians in North America. Populations even exist in the Arctic Circle. These fascinating animals drift into a state of hibernation every winter. However, during this time they actually undergo a continuous cycle of freezing and thawing, with as much as 45% of their body freezing each time. When frozen, they stop breathing, and their heart even stops beating. Wood frogs don’t dig deep holes to sleep in. Instead, they typically settle just below ground, often in piles of leaves or bark. By sleeping so close to the surface, they can actually wake up as soon as spring appears.

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Garter Snake
Garter snakes in cold climates hibernate through the winter — and it’s a communal event. The reptiles slither long distances to find perfect hibernation huddles, and they pack into burrows, one on top of the other. Scientists once stumbled on a garter hibernation den with over 8,000 snakes. Garter snakes carry trace amounts of venom that stun small animals, but it’s virtually harmless to humans, and many people keep the reptiles as pets.

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Bats
Some species of bats, the only flying mammals, hibernate. Bats that live in or migrate to warmer shores don’t hibernate, but those that make their homes in colder climates hunker down between late fall and mid-March. Like most hibernating animals, bats’ temperatures nosedive for winter sleep. But unlike some hibernators, bats don’t need to eat during their slumber. They simply shut down for six months and snooze 24/7. If you have an attic, keep an eye out for hibernating bats, as they have no problem flying in and setting up shop.

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Common Poorwill
Common poorwills are the only known hibernating birds (although other birds, like hummingbirds and doves, can enter a state of torpor). They are nocturnal and belong to the Nightjar family. They are commonly found throughout the western United States to the north of Mexico. They prefer to live in dry, open areas that have grass and shrubs and thrive in dry habitats with stony slopes and little green growth. During the cold season, many birds migrate to warmer areas; however, those who do not stay put and hunker down in piles of rocks. They can lower their body temperature and enter an extended state of torpor. Their heartbeat and breathing slow down, and they can stay that way for weeks at a time. In the fall, poorwills feast on insects. During hibernation, their bodies extract nutrients from the digested and stored bug fat.

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Fat-Tailed Dwarf Lemurs
You can find fat-tailed dwarf lemurs in Madagascar’s dry forests but don’t search in the cold months — because fat-tailed dwarf lemurs hibernate. About five fat-tails will curl up together in a hollow tree to sleep the winter away. Their heart rate slows, as does their metabolism, and their bodies instinctively survive on fat storage. In fact, they can slow their heart rate from around 180 beats per minute to just eight.

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Hedgehog
Some hedgehogs hibernate in small, dry, protected areas far away from predators. You can usually find them sleeping in abandoned rabbit holes, under woodpiles, and even in compost heaps. During the dormant period, their body temperatures lower to match their surroundings, their heart rates drop, and they cease breathing for a while.

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Bumblebees
Where do bumblebees go during the winter? Sadly, most die in the fall, but queen bumblebees build hibernation hideouts for autumn and winter, and in the spring they start new colonies. Most bumblebees hibernate in strategically located dirt holes.

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Box Turtles
There are several species of box turtles, and they are characterized by their domed shells. Unlike other animals that must make or find a suitable spot to hibernate, box turtles simply crawl inside their shells. They usually tuck in sometime between mid-September and early October and stay that way for three to four months.

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