Fun Facts About Animals With Unusual Sleeping Habits

Nearly all animals need sleep, but their ways of resting differ significantly from human routines. While they don’t tuck themselves under blankets, each species has its own distinctive method for recharging. Predators often sleep in the open, confident in their position atop the food chain, whereas prey species have evolved clever—and sometimes quirky—sleeping habits to stay alert and avoid threats. Here are some of the most intriguing and unexpected ways animals catch their Zs in the wild.

Bears Are Excellent Sleepers

Bears spend the majority of their winter resting through hibernation. Before the cold season sets in, they gorge themselves to build up fat reserves, then retreat to a secure, snug shelter—often a cave or den—where they remain asleep for several months.

While hibernating, their heart rate slows dramatically, and they neither eat, drink, nor eliminate waste, conserving as much energy as possible. Pregnant bears may briefly awaken to give birth, then return to sleep as their cubs nurse until spring comes.

Meerkats Protect The Alpha

Meerkats thrive in well-organized social groups led by dominant alpha males and females. These close-knit communities can consist of up to 50 members, all connected through a shared system of underground burrows.

When not standing guard to watch for predators or catching some rest, meerkats often huddle together in a communal pile called a “heap.” Interestingly, the alpha meerkat always takes the central spot in the heap, protected and surrounded by the other group members.

Cows Aren’t All That Sleepy

While it might look like cows spend most of their day standing or grazing, they actually only sleep around four hours daily. That’s surprisingly little for an animal that devotes so much time to feeding.

In fact, cows spend over half their lives lying down, but only a small fraction of that time is true sleep. Interestingly, cows are also known to occasionally catch some shut-eye while standing.

Desert Snails Spend Most Of Their Lives Sleeping

Desert snails are remarkably inactive, staying awake for just 5–7% of the year—that’s only about 15 to 30 days annually. The rest of the time, they enter a dormant state called aestivation, which helps them survive harsh, hot, and dry conditions much like hibernation does for cold weather.

These snails become briefly active following rare winter rains between November and March. Astonishingly, some have been found to remain in this dormant state for up to six years in museum collections before reawakening!

Sloths Can Hang If They Want To

Since they have almost no defense against predators, sloths spend nearly their entire lives up in the trees. These solitary animals, when in captivity, can sleep as much as 20 hours a day, while wild sloths usually rest for no more than 10 hours.

When sleeping, sloths often curl up in the crook of a tree or hang from a branch by their claws, keeping themselves safely out of reach from danger.

Bats Prefer Things Upside Down

Unless you’ve been completely out of the loop, you likely know that bats sleep while hanging upside down. Though it may appear strange to us, this behavior is actually a clever survival strategy for these night-active animals.

By roosting upside down in elevated spots, bats stay protected from predators. This position also enables them to launch into flight instantly if danger arises. Plus, their powerful talons grip so securely that falling isn’t a concern at all.

Elephants Are Sleep Deprived

Research reveals that these incredible creatures sleep for just about two hours daily. Since staying alert is crucial for their survival, they break their rest into brief naps to remain watchful for predators.

While they occasionally lie down for short naps, it’s far safer for them to sleep standing up, allowing a quick escape if danger approaches.

Albatross Snooze In The Air

Since these seabirds spend most of their lives soaring through the air searching for food, they have very little opportunity to rest. To adapt, they’ve developed the ability to sleep while flying.

Though it might seem risky—potentially causing them to veer off course or collide with obstacles—they have perfected a technique called dynamic soaring. This skill lets them glide smoothly on wind currents, allowing them to rest peacefully in midair.

Walruses Have Built-In Life Vests

Walruses have the remarkable ability to sleep while swimming, which is impressive given that they can swim nonstop for up to 84 hours. When resting in the water, they inflate specialized pharyngeal pouches that help keep them buoyant.

On land, walruses can sleep for as long as 19 hours and can also take brief naps underwater, holding their breath for about five minutes. In short, walruses can catch some shut-eye anytime and anywhere.

Dolphins Never Fully Sleep

Dolphins face a special challenge when it comes to sleeping—they must remain conscious to breathe. To handle this, they practice unihemispheric sleep, where one half of their brain rests while the other stays awake.

During this time, they keep one eye open to stay alert for predators and monitor their environment. This unique way of sleeping helps them avoid drowning and respond swiftly to any dangers.

Ducks In A Row

When ducks bed down for the night, they often arrange themselves in a line, creating a balance of security and rest. The ducks nestled in the center enjoy the deepest sleep with both eyes shut, while those positioned on the ends remain partially alert—sleeping with one eye open.

This behavior is made possible by unihemispheric sleep, a fascinating ability that allows one half of the brain to sleep while the other remains active. Remarkably, the ducks on the perimeter can still respond to danger in less than a fifth of a second, even while only half-awake.

Frogs Get In Tune With The Weather

Much like bears and other hibernating animals, frogs also enter a dormant state during the winter—but their method is quite unique. Frogs produce a natural antifreeze that permits ice crystals to form in their body cavities. At the same time, their bodies flood with glucose, which acts as a protective agent to shield vital organs from freezing temperatures.

While in this frozen state, the frog’s breathing halts, its heart stops beating, and all other bodily functions shut down. Amazingly, when warmer spring temperatures arrive and the frog begins to thaw, it comes back to life as if nothing happened.

Apes Make Their Own Beds

It’s no surprise that apes sleep in a way that closely resembles humans. Orangutans, gorillas, and chimpanzees often curl up to rest, much like people do. They typically build or find elevated platforms in trees to sleep on, keeping themselves safely above potential predators.

Scientists believe that these advanced sleeping behaviors—especially their ability to rest deeply and for extended periods—may have influenced their evolution. This capacity for quality sleep is thought to be linked to the development of greater intelligence, helping make apes some of the smartest animals in their ecosystems.

Sharks Need To Keep Moving

Sharks need to keep moving to ensure a constant flow of water over their gills for oxygen. This doesn’t mean they never sleep, but scientists believe that instead of entering a deep sleep, sharks shift into a kind of “auto-pilot” state where parts of their brain rest while they continue to swim.

Some researchers also suggest that certain species, like white sharks, may position themselves to face underwater currents. This allows the water to pass through their gills passively, enabling them to stay still and rest without actively swimming.

Koalas Aren’t As Lazy As We Think

Researchers have run into a few challenges when studying animal sleep patterns, particularly in distinguishing between true sleep and mere resting. Initially, it was thought that koalas in zoos were sleeping up to 22 hours a day!

It was later revealed that they actually sleep around 14 hours, with the remaining time spent resting. Koalas need this much sleep because their diet consists mainly of eucalyptus, which is energy-draining and takes a long time to digest.

Giraffes Hardly Sleep

Despite being one of the largest animals on Earth, giraffes sleep less than most. According to Animal Planet, they only sleep for about 30 minutes a day, typically in five-minute intervals.

This sleep schedule is likely a survival strategy, as giraffes live in areas with many predators like lions, cheetahs, and leopards. As a result, when they do sleep, they either rest their head on their back or sleep standing up, staying alert to potential threats.

Horses Can Sleep Standing Up

Horses sleep standing up for short periods of time, a behavior linked to their status as prey animals. Since they need to be ready to run at a moment’s notice to escape predators, standing up allows them to take quick naps while staying alert.

This is made possible by an adaptation in their musculoskeletal system that allows their limbs to lock into place when they fall asleep. However, to enter deep REM sleep, horses must lie down.

Sea Otters Anchor Themselves

Sea otters might have one of the most adorable sleep routines in the animal kingdom. Instead of heading to shore, they snooze while floating on their backs in the water to stay safe from land predators. To keep from drifting away, they wrap themselves in kelp, using it like a natural anchor.

As if that isn’t sweet enough, sea otters often hold hands while they sleep to stay close to each other. Sometimes, groups of up to 100 otters link up in what’s charmingly called an “otter raft.”

Sperm Whales Sleep Vertically

It wasn’t until 2008, that we gained a partial understanding of how sperm whales sleep when researchers stumbled upon a group bobbing vertically in the water.

Although it was assumed that these whales participated in unihemispheric sleep like other mammals, it was discovered that they engage in short periods of full sleep near the surface of the water. Today, it is still unknown if this is the only type of sleep that they get or if they have another form in deeper waters.

Penguins Sleep For Minutes At A Time

On the lookout for countless predators, penguins hardly ever really sleep. Instead, they take short naps throughout the day that are usually only minutes at a time! For extra protection, they will sleep in groups known as a rookery, which also helps create warmth.

Because some penguins can be out on the ocean for nine months at a time, it’s assumed that they can also catch small naps in the water after their last meal of the day.