Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

In the natural world, many animals have strange and unique sleeping habits that surprise us such as sleeping sea otters often 'hand in hand', hibernating wood frogs, heart will stop beating, dolphins stop. Sleep with only half of the brain… Let's find out with Toplist the animals with the strangest sleeping habits on the planet!

Top 12 Animals with the strangest sleeping habits

Polar bears

Winter in the Arctic, the temperature drops very low, leading to very scarce food. When the ambient temperature drops, making it difficult to find food, polar bears begin to hibernate. Polar bears also have a layer of fat up to 10 cm thick to help keep the body warm, even when the temperature drops to -40 degrees Celsius. Polar bears are very insulators, if observed with infrared cameras, we can only see them. only their feet. Therefore, when the winter conditions are not favorable, or when the female bears are pregnant, they just crawl into the burrow, curl up and sleep to avoid the cold and save energy.
Their sleep is usually not deep. Heart rate decreased from 70 times to 8 times / minute, body temperature did not change. They can wake up immediately when needed. When in burrows, they do not eat and live off of their body fat; During this time, they do not defecate or urinate.

Despite hibernating for a long time, polar bears almost always preserve their strength and muscular strength. They will recover from a hibernation lasting about three months, but retain more than three-quarters of their muscle strength without the need for a single drop of food or water. If humans were also immobile for the same amount of time, they would lose about 90% of their strength.

Many other animals are also forced to go to sleep in the winter because they can't run away, can't find food, or don't have thick fur to keep warm, they have to choose the form... sleep (just save energy). , hiding from predators and from the cold) like marmotte rats, or brown bears of the Pyrenees, they sleep for 6 months straight.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

Lemurs of Madagascar

Hibernation is not only associated with cold, but sometimes a response to seasonal food shortages. Like the lemurs of Madagascar (despite living in the tropics, winter temperatures can be as high as 30 degrees Celsius), they still sleep during this period because they cannot find their favorite food. During sleep, their bodies live off of the fat stored in the tail (accounting for up to 40% of the body's fat stores). During 7 months of hibernation, their body temperature fluctuates from a few degrees to tens of degrees Celsius, depending on the outside environment. By regulating body temperature according to ambient temperature, lemurs are able to reduce metabolic rate and save energy, in a way similar to lizards and reptiles.

In addition, if animals are nominated for a Grammy, the lemurs will win with their ability to sing ingeniously, in the right rhythm. Singing and rhythm in other animals have intrigued scientists for decades, in part because they can provide insight into human evolution itself.

According to a new study published in the prestigious scientific journal Current Biology, Indri indri, a lemur from Madagascar, is one of the few animals that emit rhythmic sounds. Chiara De Gregorio, a researcher at the University of Turin, Italy, who co-authored the study, said that the sound of Indri indri lemurs emitted at low and high altitudes penetrates the air. "The rhythm lemurs produce is inclusive of sound and silence," says Chiara De Gregorio.

Collecting recordings of the 'singing' of lemurs is no easy task. The tree-dwelling lemurs, deep in the rainforest canopy of Madagascar. Researchers have spent years monitoring them in the woods to try and hear them sing. However, there are days when lemurs don't sing at all.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Bats often hang upside down when they sleep. Perhaps bats are the only mammals that choose to sleep like that. Bats are the only animals that can fly; The hind legs are short and small, connected to the wing membranes, so it is difficult to move. So when they fall to the ground, they cannot stand up, nor walk. Therefore, bats are only suitable for climbing to a high place, hanging upside down, when in danger, just let go and spread their wings to fly.

Moreover, in winter, in the hanging upside down position, the bat will reduce direct contact with the cold cave ceiling, bury its head and body in the wing membrane, with thick mattress feathers on its body, which has the effect of preventing away from the cold outside air.

When sleeping, bats turn their heads down and their feet firmly cling to something to supply enough blood to the brain, helping to slow down blood metabolism. This sleeping position also helps the bat to escape quickly when needed. Unlike birds or insects, the leathery wings of bats are not strong enough to easily lift them from the ground into the air. Therefore, when resting, bats always choose a high position so that when they need to fly, they just drop down, taking advantage of air resistance to support take-off.

To adapt to their resting state and unique flight mechanism, bats evolved to have a compact size, the heart can easily circulate blood even when upside down. In addition, to support the large amount of oxygen needed when flying, bats have a specially developed heart that is three times larger than other mammals of the same size and has a higher blood transport capacity. Its right atrium is very large, when the right atrium dilates, it can pump a lot of venous blood.

While humans or animals must grip and use muscular energy to grasp something, bats do not. Their claws are unique in that they do not use energy to cling to objects. In addition, when winter comes, bats also hang upside down to hibernate, thus reducing exposure to the cold top of the cave. Or there are some bats that can bury their heads and bodies in the membrane of their wings, which, together with the thick, soft feathers on their bodies, can have the effect of separating them from the cold air outside.

Bats can hang upside down for long periods of time, including during hibernation and even after death. Some species of bats can hibernate for five to six months and survive through the small amount of fat their bodies store. Usually, bats become active around dusk and leave the nest to hunt for food.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

Swallow at Swainson

Blackbirds can sleep standing right on a tree branch without falling to the ground. The secret lies in the tight ligament system in the bird's feet, which helps the foot firmly grasp the branch. In addition, because the brain of birds is more developed than that of reptiles, the cerebral hemispheres have not yet wrinkled, but have increased in size. The cerebellum is the most developed, the visual lobes are very large, making them able to balance very well even during sleep.

With migratory blackbirds, they fly away continuously. Their flights are usually at night. Swainson's blackbirds have to fly about 3,000 miles from their habitat, breeding to warm sunny areas of South America, Canada and Alaska. When spring comes, they continue a journey from South America back to their homeland. When do they sleep?

Scientists have discovered that they stay awake all night and rest during the day. However, instead of long naps, they would sleep in several bursts, averaging 9 seconds each. This bird also sleeps in a few different ways. Sometimes they only close one eye, while the other eye and half of the brain are still active, helping them avoid lurking dangers. Sometimes they close both eyes, but only doze off.
Its original distribution is Europe, Asia and North Africa; Thanks to human activities, the blackbird has also extended its distribution to Australia and New Zealand. This species has several subspecies across its wide range; A few of the Asian subspecies are sometimes considered full species. Depending on the latitude, this common bird can be a settled, partially migratory, or fully migratory species.

Males of the specified species, found throughout much of Europe, have all black plumage except for the eye ring and yellow bill and have a melodious song; Adult females and juveniles have predominantly dark brown plumage. This bird breeds in forests and gardens, building neat, cup-shaped nests lined with mud. It is omnivorous, eating a wide range of insects, earthworms, berries, and fruits.

Both males and females occupy separate breeding grounds, and present a clear threat to intruders, but they are more gregarious during migration and in wintering areas. . Pairs of birds stay in their territory year-round in a sufficiently temperate climate. This common and conspicuous bird has given rise to a number of literary and cultural references, frequently relating to their song.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Have you ever wondered how giraffes with four "long and long" legs and long necks will have a sleeping position? During "light sleep", the giraffe sleeps only part of its brain and its neck is still held high. Only when sleeping deeply, giraffes put their head on the tail, but the time should not exceed 20 minutes. Because the giraffe is often attacked by a lion suddenly, it uses the secret of "sleeping while awake", combined with "sleep for a short time" to guard against predators. In doing so, they achieve their goal of being both safe and able to get proper rest.

Through studying animals' sleep, researchers found that when animals sleep, the brain can emit electromagnetic waves like the human brain, so animals can also dream. Some species dream a lot, for a long time, there are species that dream less, for a shorter time. For example, squirrels and bats dream frequently, birds dream relatively little, and reptiles almost never dream. This may involve them having to stay alert to the enemy at any time, in order to be able to escape in time.

In addition, giraffes are the few mammals that sleep the least, averaging only half an hour a day. Every time I sleep, I only take a few minutes of sleep. At that time, they fall into a state of half-awake and half-sleep to guard against dangers in the wild. In captivity, giraffes can sleep 4-5 hours a day. Giraffes are animals that belong to the same genus as deer and oxen, but are grouped differently from the others, the Giraffes, which include giraffes and a closest family, the striped giraffes. . The giraffe's range extends from Chad to South Africa.

Giraffes can live in savannas, grasslands or mountains. However, when food becomes scarce, they will venture into more wooded areas. They often prefer to live in areas with a lot of acacia trees. This species usually drinks large amounts of water at one time and can retain water for a long time in the body, so they can live in arid places for a long time.

Giraffes can run fast and in an emergency can reach a gallop of 55 km/h, meaning that over short distances they can overtake racehorses.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

Wood frogs

Wood frogs from North America to the Arctic Circle also hibernate. However, their hibernation habits are vastly different from other creatures, even considered "unique" in the natural world. Specifically, when it begins to feel the cold of winter, the wood frog will go into a special hibernation state by stopping all life functions, from the heartbeat to brain activity, like it is Freeze the whole body. During this process, ice crystals can even grow from the frog.

When the weather warms up, the wooden frog's body will be defrosted, all vital functions are restored and they can return to normal life. According to records, wood frogs can survive in a frozen state for 8 months and come back to life without any damage. The reason for this special ability, the scientists pointed out, is that in the tissue of wood frogs there is a high concentration of cryoprotectants. In addition, their liver has the ability to break down glycogen compounds into glucose (sugar) and pump it straight into the bloodstream. Blood sugar stabilizes cells and prevents dehydration, helping them survive the freezing cold.

The Alaskan wood frog can petrify for nearly 7 months at an average temperature of -14.6 to -18 degrees Celsius, then come back to life in the summer, they are cold-tolerant when it can petrify for nearly 7 months at an average temperature of -14.6 degrees Celsius, even -18 degrees Celsius. Come spring, they come back to life. During hibernation, more than 60% of the wood frog's body freezes, the animal stops breathing and the heart stops beating. The physical aspect as well as the metabolic and elimination activities in the body stop, just like the state of death.

In fact, wood frogs can go through 10-15 freeze/thaw cycles over the course of a winter. The change in temperature causes the frog's body to expand and freeze as night falls. At the same time, molecular mechanisms allow the wood frog's body to effectively carry out petrification. In the tissues of wood frogs there is a high concentration of cryoprotectants. These are solutes, including glucose and urea. Their liver is able to break down glycogen compounds into glucose (sugar) and pump it straight into the bloodstream. Blood sugar stabilizes cells and prevents dehydration, helping them survive the cold.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

Sea Otter

Sea otters live mainly along the Pacific coast of North America. This animal not only has a lovely appearance but also makes our hearts "melt" by the habit of sleeping "hand in hand". This romantic act stems from the fact that sea otters have a habit of sleeping right in the water in a supine position, which makes them vulnerable to waves. Therefore, to avoid "waking up in a distant place", there will be dozens of otters holding hands while sleeping, forming a solid "raft" fixed on the water. In the case of sleeping alone, sea otters will wrap seaweed around their bodies to avoid being hit by the waves.

Otters have a thick (1,000 hairs/mm²) inner coat protected by an outer coat that keeps them dry underwater and traps a layer of air to keep them warm. All otters have long, thin, and flexible bodies; short and webbed feet. Most have sharp claws to capture prey, but South Asian short-clawed otters have only vestigial claws, and two closely related African otters have no claws: these species live in rivers. mud-filled areas of Africa and Asia and locate prey by touch.

Otters do not depend solely on their special plumage to survive in cold water where many species live: they also have a very high metabolic rate and expend energy at a profligate rate: otters Eurasian fish, for example, must eat 15% of their body weight each day; Sea otters range from 20 to 25%, depending on the temperature. In 10°C water an otter needs to catch at least 100g of fish per hour, less than that it will not survive. Most of them hunt for 3-5 hours a day, if a nursing mother needs to hunt for 8 hours a day.

Most otters eat fish as the top food on their menu, in addition to frogs, shrimp and crabs; Some also specialize in eating shellfish while others eat small mammals or birds.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Dolphins have very special sleeping habits, they only sleep with half of the brain hemisphere and one eye. This is called “slow-wave hemispheric sleep”. Specifically, when sleeping, half of the dolphin's brain hemisphere will stop working and they will close one eye on the opposite side. For example, if the left hemisphere of the brain is deactivated, the dolphin will close its right eye. The eyes and the other half of the brain are still functioning normally.
There are three reasons given by scientists to explain the special ability of dolphins to sleep. Firstly, unlike fish with gills, dolphins are mammals and must constantly come to the surface to breathe. If dolphins sleep and fall into an unconscious state like humans, they are quite likely to drown. Therefore, leaving half of the brain at rest, the other half active will help dolphins come to the surface to exchange air through the hole located at the bottom of the neck.
Second, "slow-wave hemispherical sleep" helps dolphins detect other dangers in the ocean. Third, this type of sleep helps dolphins maintain physiological activities such as muscle movement to help maintain body temperature in cold seawater.

A recently published study has revealed the surprising ability of dolphins: They can stay awake for days or weeks at a time without sleep. So how can they survive without sleep? Dolphins possess a very special sleep mechanism, they can let half of their brain rest at a certain time while the other half is still awake - a process called "Unihemispheric sleep". This special sleeping mechanism not only keeps dolphins from drowning, but also allows them to stay alert to any danger and even encourages brain development.

In addition, dolphins use the toxins of their prey as "addicts". We know that puffer fish have strong toxins. Apparently dolphins know this too, but they use it for 'high' purposes. Usually, the puffer fish toxin is deadly. However, in small doses, it can act as a narcotic. The BBC once filmed a video in which dolphins gently play with a puffer fish for 20 to 30 minutes, then hang around and behave "weird".

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Meerkats always lie on top of each other to sleep and their ears are always pricked up to listen for strange noises. The team further discovered that each animal's sleep is influenced by its ability to survive in the environment. The animals most likely to become prey, will sleep less than other animals at the top of the food chain.

For example, meerkat civets have a habit of lying on top of each other in the nest to sleep, with one ear always raised to listen for danger. In which, the queen in the herd will lie in the middle and have the deepest sleep. The civets holding the guard post will sleep outside and always wake up first if there is any noise.

Meerkat are small burrowing animals that live in large underground burrows with many entrances and usually leave during the day, unless it is necessary to avoid the sun in the afternoon. They live very orderly, averaging 20 to 30 members. Meerkat in the same group regularly groom each other to strengthen social bonds.[19] The leader pair often emits a characteristic scent - a sign of their power in the group. This behavior is also often performed when the members of the herd are reunited after a short time out. Especially when all the meerkats are siblings or children of the leader pair.

Meerkats show mutual concern in the herd, with one or more meerkat standing guard while the others are foraging or playing, to warn of approaching danger. When a predator is discovered, Meerkat acts as a sentinel to sound a warning, and the other members of the party will run and hide into one of the small niches and spread the word across their territory. The sentry Meerkat was the first to emerge from the burrows and search for predators, constantly shouting to alert the others down the burrow. If there is no threat, the sentinel Meerkats stop the signal and the others feel safe to appear.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Flamingos sleep with one eye closed, one eye open to always be on the lookout for nocturnal predators.

Flamingos often gather in large flocks to forage, live in shallow water, whose feather color depends on daily food. Flamingos are considered one of the loyal animals. Birds in the same flock will move together when facing threats. When a research plane approached the flamingo colony in Sisal, Mexico, the birds moved together to a safer place without dispersing individually.

When born, flamingos have white plumage. The color of the flamingo's feathers is later formed by the food source where they live, which can vary from pale pink, orange pink or crimson. Pigments found in the marine shrimp in the Yucatan, where these flamingos live, give their plumage the color of coral reefs.

A pair of flamingos are using their beaks to feed a baby bird. This is also the place where the parents nest to welcome the eggs that are about to hatch. When the eggs hatch, the chicks are fed with a fat- and protein-rich milk produced in the parent's intestinal tract.

When the chicks are a little older, the parent flamingos will leave them in the care of other adult birds to feed and feed, then return to feed them in the evening. Despite being watched over by larger birds, young birds are still vulnerable to threats from other animals.

Flamingos wake up before dawn, go in large flocks to find food. Flocks of flamingos can travel hundreds of kilometers in search of food

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits

Yellow-cheeked chipmun

The golden squirrels have a knack for balancing on a tree branch while they sleep, and the slightest movement wakes them up instantly.
The yellow-cheeked chipmunk or redwood chipmunk is widely distributed in California. Their range is a small area along the northern coast of California. Extends no more than 40km from the coast. The species' range begins in Sonoma County and extends north to the Eel River, in Humboldt County. Their entire range is less than 20,000 km squared.

These squirrels burrow to store food and avoid predators. These burrows are very wide and are made in dense canopy of trees and dense trees. This animal relies on coastal redwood forests and mixed forests of conifers or Douglas fir for habitat. Although they are rarely found in the canopy. One study found that chipmunk densities of this group were significantly greater in old-growth forest, compared with secondary forest.
These squirrels reach a size of about: 233 to 297 mm in length and weight: 78 - 118 grams. The yellow-cheeked chipmunk has a cheek pouch like a mouse. With these cheek pouches can help them store a large amount of food. Their cheeks are puffy and have a characteristic yellow color. Small triangular ears are placed on the top of the head. The almond-shaped eyes have a jet black tone and white eye rims.

On their back there will be alternating black and light brown stripes. Underneath is equipped with quite soft white fur. Sometimes the belly will be covered with light brown or light yellow hair. Their winter coat is longer, softer and thicker. Yellow-cheeked chipmunks exhibit mild sexual dimorphism. Females are on average about 5% larger than males.

Top 12 Animals with the strangest sleeping habits

Top 12 Animals with the strangest sleeping habits


Koala is also known by the familiar name of the koala or the scientific name is Phascolarctos cinereus. This animal spends 20 to 22 hours a day sleeping, leaving only a very short time to exercise. They are the largest herbivorous marsupial in Australia. The only living animal in the family Phascolarcidae and its closest living relative is the wombat.

This sleeping animal is distributed along the east and south coasts of the main island, precisely in Queensland, New South Wales, Victoria and South Australia. Their body is about 60–85 cm in length and lies in the weight range of 4–15 kg. The coat is silver gray to chocolate brown. Koala populations in the north are generally smaller and lighter in color than those in the south.

Koalas are medium sized animals. The muzzle is flattened, the eyes are small, the animal seems to be a bit blind. The dark nose is also slightly flattened, but it is quite large and leathery. The teeth used for the processing of hard leaves are very strong, the incisors are distinguished by their sharp edges. The ears are round, very widely spaced, relatively large, with long hairs on the edges.

All limbs are elongated, because you have to constantly move through the trees. Therefore, the brush of the upper foot consists of several parts – for ease of movement. The legs are lower, and they are not so strong. The claws of a wood bear have several advantages: long and curved in an arc. Thanks to such qualities, it is very convenient to stay on the branches, and you can hold up to 15 kg of weight.

What scientists were quite surprised at that time was the animal's fingerprints. It turns out that in all respects it corresponds to the human imprint. There is an unusual fact, and it concerns the structure of the sexual organs. Females have as many as two vaginas and two uteruses. Accordingly, males have two penises.

But the Koala brain is surprisingly small compared to its total mass – only 0.02%. Presumably, the ancestors of this species were more intelligent, had a larger brain volume, but since Koala life did not imply much brain activity, similar evolutionary changes occurred. However, this sympathy for him did not decrease. The fur of the animal is short and thick, very pleasant to the touch. By the way, this quality of hers led to animals being massively destroyed by humans because of the attractiveness of furs. The color of the coat is usually smoky gray, and on the much lighter belly, a brown tint can also occur.

Top 12 Animals with the strangest sleeping habits

Above are the top animals with the strangest sleeping habits on the planet today that Toplist learns and provides to readers. Follow along to know more interesting things about the animal world in the following articles.

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  3. Mother and child in the animal world
  4. Strange blind salamander, takes 10 years to eat a meal, 12 years to mate but can live for a century