The bear goes into hibernation. Features of animals: why the bear hibernates. What conditions are needed for sleep

Introduction.

At the lesson of the world around us, we talked about how animals prepare for winter with the onset of autumn. I learned that the squirrel makes reserves, the mole digs additional passages underground, the ants close the passages to the anthill, the wild boar accumulates fat so that they are not afraid of cold and hunger, many birds fly south, and bears look for a den to hibernate.

And then I was interested in the question: “why does the bear hibernate?” Here's what I learned with the help of a teacher, parents and an encyclopedia

Bear appearance.

Bears are the largest of modern predatory animals. There are 8 types of bears: brown bear, sloth bear, polar bear, white-breasted bear, baribal, Malay bear, spectacled bear.

The body length of modern bears is 110-300 cm, the height at the withers is up to 135 cm, and the weight is up to 700 kg. The body is powerful, the neck is thick, usually long, the head is large, the eyes are small, the ears are rounded. The fangs are powerful, while the other teeth are wide and flat, which is due to the mixed type of nutrition. Paws are strong, five-fingered. All fingers touch the ground, armed with long, curved claws. The tail is short, almost invisible. The wool is dyed black, brown or white. Some species have light spots on the chest and around the eyes. The giant panda has a combination of white and black fields.

Bears have very few enemies other than humans. Polar bears do not have them at all, a brown bear may have an Ussuri tiger (in rare cases), a white-breasted bear may have a tiger and wolves.

What is hibernation.

Hibernation, or winter sleep, is an important protective "adaptation" of the body of warm-blooded animals such as bears, raccoons, badgers, hamsters, marmots to endure adverse food and climatic conditions. The main meaning of hibernation is to save energy during adverse natural conditions: lack of food and frost.

Bears are omnivorous animals, but prefer to eat plant foods: berries, fruits, nuts, also insects, fish, and less often small animals.

The onset of winter cold entails a lack of feed, food and water become difficult to access, and this can lead to the death of the animal. Bears have adapted to survive in the cold by hibernating for several months.

The bear prepares thoroughly for hibernation, he must definitely accumulate a lot of fat (up to 30 - 40% of his weight), which he will eat little by little throughout the winter. In order to collect the required amount of fat for the winter (approximately 50 kg), the bear needs a lot of food. During this period, he eats up to 700 kg of berries or about 500 kg of pine nuts, not counting other feeds. In lean years, bears can visit oat and corn crops, and some even attack livestock and apiaries.

The weight of a sleeping bear reaches up to 180 kg, but during the winter sleep the beast loses up to 80 kg. And the female also needs to provide milk for the cubs, which will be born in the den and come to the surface only in the spring. Depending on climatic and other conditions, the "master of the forest" spends from 4 to 6 months in the den, the bears hibernate in October-November and wake up in March-

April. She-bears with cubs stay in the den the longest, old males sleep the worst.

A brown bear usually dens in a secluded dry place, in most cases in pits covered with windbreak, or under upturned tree roots. Less commonly, bears dig a shelter in the ground or occupy caves and rock crevices. In addition, a bear can arrange a den for itself both in a hollow tree and on dry hummocks among swamps. Before entering the den, the bear collects moss and grass for bedding, twists it all, and then, backing away, drags it into the den.

As a rule, the bear sleeps in a separate den and all alone. There are cases when a stronger bear drives its weaker owner out of the den. Only the female sleeps with her little cubs. Before leaving for the last time in the den, the bear confuses the tracks. Sleeping bear curled up. Its hind legs are tucked in, and its front legs cover its head. The paws are usually at the level

nose, so it seems to many that the bear is sucking its paw. Hunters can wake up the bear. They usually don't fall asleep after that. Such bears are called "rods".

During hibernation, all life processes almost stop. The body temperature drops, breathing slows down, the heart beats weakly. But even during this period, animals are able to control their condition - if the temperature or humidity changes in their "homes", they wake up and start looking for another place to sleep.

Does the polar bear sleep?

But not all bears hibernate. This does not happen with polar bears. In winter, polar bears sleep more than in summer, but this is not the well-known hibernation of animals. The temperature and breathing of polar bears remain normal. They sleep in burrows and caves made of snow and ice. During warming, bears can roam all day and even at night.

Female polar bears sleep more in winter than males. During this winter sleep, cubs are born. In October, a she-bear in powerful deposits arranges a lair in the form of a vast cave. No matter what the temperature is outside, in bear dens it is always close to zero. In December - January, one or two bear cubs are born, blind and deaf, no larger than a kitten. They remain in the den for about 2 months. By this time, the cubs have erupted their teeth and opened their eyes and auditory openings. In March or early April, the mother bear brings her offspring outside.

Poetry, riddle.

Why does a bear sleep in winter?

Bear, bear! What happened to you?

Why do you sleep in winter?

Because snow and ice

Not raspberries and not honey.

Mystery

He is furry, he is big,

He sleeps in a den in winter,

Chewing berries in summer

Takes wild honey from bees

Terrible can roar

The clumsy beast……(bear)

Conclusion.

So, bears hibernate in order to more easily survive the harsh and hungry winter.

And in conclusion, I want to know if you listened carefully to my story? Please answer the question "Who goes to hibernation?"

Bibliography.

1. "Great Atlas of Animals.-Moscow "Rosmen" 2003
2. Tsekhanskaya A.F., Strelkov D.G."The Complete Encyclopedia of Animals".- M.: CJSC "Rosmen - press", 2009.
3. S. Starikovich "Wonderful Animals"Stories. Moscow, "ROSMEN", 1994
4. Series subscription "in the wild world."
5. The Big Book Why. Translation from Italian by Olga Zhivago. Moscow, "ROSMEN", 2003

1. Introduction.
2. Bear appearance.
3. What is hibernation?
4. How does a brown bear prepare for hibernation?
5. Does the polar bear sleep?
6. Conclusion.
7. Poetry, riddle.
8. Bibliography.

Instruction

Winter sleep is the main feature of bears and many other animals (badgers, hedgehogs, moles, frogs, reptiles, etc.), which is a kind of measure of their protection from long and cold winters. During winter sleep, the body of animals begins its complete restructuring: breathing becomes rare, the heartbeat slows down, and the body temperature drops. Animals go into suspended animation.

If we talk about bears, then they fall into this state because they do not bother to make any supplies for the winter in time, as squirrels, hamsters and other animals do. Despite the fact that bears are predators of impressive size, their main food in the summer is berries, mushrooms, plants, which disappear with the advent of cold weather.

In addition, during the summer, bears gorge themselves and accumulate a huge layer of subcutaneous fat, which will be enough for them not to want to eat during hibernation. It is the accumulated fat reserve that allows the bear to forget about winter sleep for whole months, not remembering severe frosts and winter hunger. Of course, there is a possibility that berries or other fruits will be under the snow, but they will not be able to satisfy the hunger of the beast, whose weight can reach half a ton. It is curious that some species of bears take care of their lair before the "winter rest". So, they equip their winter dwelling with branches and twigs.

It is worth noting that not all bears forget their winter sleep just to survive hunger. For example, female polar bears fall into being. It is curious that this process in polar bears can occur at any time of the year, but most often it happens. Polar bears do not equip their lairs, they just dig big holes.

It is also curious that bears suck their paw during winter sleep. There are several versions explaining this behavior of clubfoot predators. According to the first version, the animal helps the molting process by biting the old skin on the paw. The fact is that on the feet of the bears there is a rather thick layer of skin that helps these animals move faster on rough and uneven ones, and the bears suck them.

The second version says that the bear thus eats up the remnants of plant food on its paw. The fact is that during the summer period a huge number of different berries, fruits, leaves, insects stick to the feet of this predator. Over time, they trample, dry out and turn into a kind of "dry ration", which serves as an addition to winter sleep. This allows clubfoot to see dreams and suck on berries.

For those who have wings, it's good - they flew away and that's it. well and brown bear through thickets and wild forests one cannot reach places where the climate is warmer.

And he finds a pretty practical solution. In the summer, the bear eats off, then to hibernate until the very spring. But not everything is as simple as it might seem at first glance. Imagine what you would look like if you didn’t drink and eat for six months. Let's get acquainted with some of the amazing processes that occur in the body of a bear during hibernation.

busy summer

To prepare for the semi-annual "fasting", the she-bear needs to make energy reserves. So she doesn't worry about her figure. Its main goal is to accumulate more subcutaneous fat (in some places its thickness reaches eight centimeters). Although she likes sweet berries the most, she is not picky about food. She eats everything: roots, small mammals, fish and ants. By autumn, she can gain weight up to 130-160 kilograms, a third of which is fat. (The weight of a male can reach up to 300 kilograms.) Before plunging into the world of dreams, she stops eating and frees her intestines. For the next six months, she does not eat anything, does not urinate or defecate.

Bears choose a place for a den in a cave, an abandoned anthill or a depression under the roots of trees. The main thing is that it was quiet there and no one disturbed the sweet dream. Bears collect spruce branches, moss, peat and other materials to make a warm and cozy bed. The lair is not much larger than the massive body of a bear. When winter comes, snow will cover the lair and only a careful observer will be able to see the hole through which air enters.

hibernation

Some small mammals, such as hedgehogs, bats and dormice, fall into the real hibernation, that is, spend most of the winter in a state similar to death. Their body temperature approaches the ambient temperature. But the bear's body temperature drops only 5 degrees Celsius, so his sleep is not that deep. "You can't say that a bear 'sleeps without its hind legs'. A bear raises its head and rolls from side to side almost every day," says Raimo Hissa, a professor at the University of Oulu in Finland, who has devoted many years to studying bear hibernation. Yet the bear rarely goes out from her lair in the middle of winter. During hibernation, the animal's body works "in economy mode. The heart rate drops to 10 beats per minute, and the metabolic process slows down. When the bear sleeps sweetly, fats begin to be burned in her body. Fatty tissues are broken down by enzymes and supply the animal's body with the calories and water it needs.Even though the life-sustaining processes in the body are slowing down, a certain amount of waste is produced as a result of metabolism.How can a bear get rid of them and still keep her den clean?Instead of removing waste the body processes them!

Professor Hissa explains: "Urea from the kidneys and bladder is reabsorbed into the bloodstream and transported by the circulatory system to the intestines, where it is hydrolyzed by bacteria into ammonia." Even more surprising is that this ammonia goes back to the liver, where it is involved in the formation of new amino acids that form the basis of proteins. By converting waste products into building materials, the bear's body feeds itself during the long hibernation period!

In the old days, people hunted bears sleeping in dens. Sleepy Toptygin became easy prey. First, hunters on skis found a lair, then surrounded it. After that, the bear was awakened and killed. Today, winter bear hunting is considered cruel and banned in most of Europe.

Studying hibernation of bears

The department of zoology at the University of Oulu has been researching the physiological processes by which animals adapt to the cold for several years. Brown bears began to be studied in 1988, and a total of 20 individuals were observed over the years. A special lair was created for them in the zoological garden of the university. To measure body temperature, study metabolism, vital activity, as well as changes that occur during hibernation in the blood and hormones, scientists used computers, video cameras, and did laboratory tests. Biologists collaborated with specialists from other universities, even Japanese ones. They hope that the results of the research will be useful for solving problems related to human psychology.

New life

The bear sleeps all winter, turning from side to side, but an important event takes place in the life of the bear. Bears mate in early summer, but the fertilized cells inside the body of the expectant mother do not develop until the bear goes into hibernation. Then the embryos attach to the wall of the uterus and begin to grow. After only two months (in December or January), the body temperature of the expectant mother rises slightly, and she gives birth to two or three cubs. After that, her body temperature drops again, although it does not become as low as before childbirth. Daddy bear does not see how his children are born. But the sight of newborns would probably disappoint him. It would be difficult for a huge dad to recognize these tiny creatures weighing less than 350 grams as his offspring.

The mother bear feeds her cubs with nutritious milk, this depletes her already weakened vitality. The cubs grow quickly, by spring they become fluffy and already weigh about five kilograms. And this means that in the small "apartment" of the she-bear there is a revival.

Spring

March. The cold winter has passed, the snow is melting, the birds are returning from the south. At the end of the month, male bears crawl out of their lairs. But the female bears remain in their hiding place for several more weeks, perhaps because the cubs take a lot of strength from them.

After a long hibernation, a well-fed bear leaves skin and bones. The snow melted, and her fat melted with it. For all that, the she-bear is surprisingly mobile - no bedsores, cramps or osteoporosis. Some time after leaving the den, she cleans the intestines. Bears usually start eating only two or three weeks after waking up, as the body does not immediately get used to the new conditions. But then they wake up remarkable appetite. But since nature itself has recently awakened from its winter sleep, at first there is not much food in the forest. Bears chew grubs and bugs, eat old corpses, and sometimes even hunt reindeer.

The care of raising cubs falls on the shoulders of the she-bear, and she protects her cubs like the apple of her eye. An ancient proverb says: “It is better for a man to meet a she-bear without children than a fool with his foolishness” (Proverbs 17:12). In other words, it is better not to meet with either one or the other. “A mother bear has a lot to worry about. If a male bear approaches, she immediately forces the cubs to climb the tree. The point is that the male can harm them even if he is their father,” Hissa explains.

The cubs spend another winter in the den with their mother. Well, next year they have to look for their own lair, as the she-bear will have new tiny babies.

We already know a lot about the complex and unusual phenomenon of hibernation in bears, but much remains a mystery. For example, why does a bear get sleepy in autumn and why does he lose his appetite? Why doesn't he get osteoporosis? Revealing bearish secrets is not easy, and understandably so. Everyone has their own secrets!

It's no secret that the Siberian winter is a difficult test for many animals, and bears are no exception.

In common parlance, it is said that the bear hibernates, biologists say - in winter sleep. There are few details about this interesting process. The main reason is the complexity of data collection.

The brown bear is found everywhere in the reserve, both in all types of forests and in the mountain-tundra belt. On the territory of the reserve, it makes seasonal movements from forests to the high-mountain belt and back, often using trails and country roads for roaming.

What does a bear eat before hibernation?

Before laying in a den, the owner of the taiga needs to accumulate nutrients. The bear is an omnivore, but most of its diet in the Kuznetsk Alatau, as in many other places, consists of food of plant origin: berries, herbaceous plants, acorns, nuts.

Pine cones are one of the bears' favorite treats and one of the best fattening foods. Young animals can climb trees after them and break off branches. But mostly they collect fallen cones from the ground. To get to the nuts, the bear collects the cones in a heap and crushes them with his paws, from where he then, lying on the ground, selects the nuts along with the shell with his tongue. The shell is partly thrown away during the meal, and partly eaten.

Often the attention of the bears is attracted by the stocks of nuts made by the chipmunks. Digging the holes of animals, the bears get to the nuts and eat them, often together with the owner. They do not miss the opportunity to feast on ant larvae, bird eggs or fish, they also hunt small rodents and hoofed animals. The brown bear rarely kills wild ungulates on his own, he mainly devours them in the form of carrion or selects the prey of other predators (wolf, lynx, wolverine).

The facts of eating by a predator of such species of wild ungulates as an elk, a deer, a roe deer are known. He fills up prey or found carrion with brushwood and keeps nearby until he finishes the carcass completely. If the animal is not very hungry, it often waits for several days until the meat becomes softer.

It is very important how fruitful the year was for fattening feed. Bad harvest years can greatly delay the timing of bears in dens, and the animals can continue to feed even in twenty-degree frosts and almost half a meter of snow, digging cones from under the snow, trying to gain the fat reserve necessary for wintering. In years favorable for food, adult bears accumulate a layer of subcutaneous fat up to 8-12 cm, and the weight of fat reserves reaches 40% of the total weight of the animal. It is this fat accumulated over the summer and autumn that the bear's body feeds on in winter, experiencing the harsh winter period with the least hardships.

Hungry years lead to rod bears

These are animals that have not had time to gain a sufficient supply of fat, which is why they cannot hibernate. Rods, as a rule, are doomed to death from hunger and frost or from a hunter. But not every bear that meets in the winter in the forest will be a connecting rod. During "after-hours" bears appear in the forest, whose sleep in the den is disturbed. Normally well-fed, but pulled out of hibernation, the bear is forced to look for a new, calmer haven for sleep. Often the sleep of animals is interrupted by human anxiety.

bear den

Before going to the den, the bear diligently confuses the tracks: it winds, goes along windbreaks and even goes backwards in its own footsteps. For lairs, deaf and reliable places are usually chosen. Often they are located along the edges of impenetrable swamps, along the shores of forest lakes and rivers, in windbreaks and logging sites. The brown bear arranges its winter dwelling in recesses under twisted roots or tree trunks, sometimes on a pile of brushwood or near an old woodpile. Less often, he chooses a cave for his house or digs deep earthen holes - ground lairs. The main condition is that the dwelling should be dry, quiet and isolated from the presence of unexpected guests. One of the signs of the proximity of the den is large bald spots in the moss, gnawed or broken trees. The beast insulates its shelter with branches, and layers of moss lines the litter. Sometimes the bedding layer reaches half a meter. It happens that several generations of bears use the same den.

At the beginning of winter, bears have offspring

From one to four, but more often two bear cubs are born. Babies are born blind, without hair and teeth. They weigh only half a kilogram and barely reach 25 cm in length. It is interesting that the nipples of female bears are not located along the line of the abdomen, as in most animals, but in the warmest places: in the armpits and inguinal cavities. The cubs feed on 20% fat milk from their still-sleeping mother and grow quickly. In a few months of such food, the cubs are completely transformed, and they leave the den already furry and nimble. True, still very dependent.

How does a bear sleep in a den

In the den, warm and safe, the bears sleep through the long and cold winter. Often the bear sleeps on its side, curled up in a ball, sometimes on its back, less often it sits with its head between its paws. If the animal is disturbed during sleep, it easily wakes up. Often the bear itself leaves the den during long thaws, returning to it at the slightest cold snap.

Animals falling into hibernation (for example, hedgehogs, chipmunks, etc.) become numb, their body temperature drops sharply, and, although vital activity continues, its signs are almost imperceptible. In a bear, the body temperature drops slightly, by only 3-5 degrees and fluctuates between 29 and 34 degrees. The heart beats rhythmically, although more slowly than usual, breathing becomes somewhat less frequent. The animal does not urinate or defecate. Any other animal in this case would have been fatally poisoned in a week, and bears begin unique process of recycling waste products into useful proteins. A hard plug forms in the rectum, which some call a "sleeve". The predator loses it as soon as it leaves the lair. The cork consists of tightly pressed dry grass, the hair of the bear itself, ants, pieces of resin and needles.

Brown bears sleep alone, and only females who have cubs of the year go to bed with their cubs. The duration of hibernation depends on weather conditions, health and age of the animal. But usually this is the period from the second half of November to the first half of April.

Why does a bear suck its paw

There is a funny opinion that a bear sucks its paw during hibernation. But in fact, in January, February happens change of hard skin on the paw pads, while the old skin bursts, flakes, and itches a lot, and in order to somehow reduce these discomfort animal licks its paws.

It took more than one thousand years of natural selection to form such a complex system of adaptations, as a result of which bears acquired the ability to survive in areas with harsh climatic conditions. It remains only to be surprised at the diversity and wisdom of nature.

Previously on Bears:

To answer this question, let's first understand what hibernation is. Hibernation is a physiological state, similar to very deep sleep, which a number of mammals fall into during the period of winter cold, or during very hot summers in the tropics. At the same time, there is a significant decrease in the vital activity of the animal's body, which saves it from death for a period of long sleep without food and water.

Hibernation is not the same for all species, having a different depth and degree of depression of vital signs. Some mammals fall into a deep and prolonged sleep, while others periodically wake up and are reinforced by reserves prepared in advance for the winter (for example, protein). Not only mammals, but also some amphibians, insects and even fish fall into hibernation.
The bear is one of the representatives of mammals, which hibernates for the winter. This fact is known to all. He has such a need for the reason that he does not store food for the winter, and during this period of the year his food is not available in nature. The bear feeds mainly on plant foods. Hibernation is the only chance for survival, but the bear has to prepare for it all the time during the warm season. He eats intensively and accumulates fat reserves. During hibernation, the bear's body temperature quickly decreases, breathing becomes slower, and the heartbeat slows down significantly. With the onset of heat, the bear comes out of this state and continues the process of fat accumulation. Waking up a bear during hibernation is strictly forbidden and even dangerous. The bear wakes up very angry, but after that it may not hibernate again and simply die. How does an animal understand that spring has come and it's time to wake up from hibernation? They are informed about this by an increase in air temperature, which they feel, as well as a strong feeling of hunger. During hibernation, the bear sucks its paw, and this is not at all because it is very hungry, but because of the need to moisturize the dry skin on the feet, as well as to remove keratinized skin. During the hibernation period, the bear gives birth to babies. The cubs are born very tiny and blind, and during the entire hibernation of the mother they feed on her milk.
Not all bears hibernate. Polar bears usually do not hibernate. This need is resorted to only by pregnant females and those who feed the cubs. The rest of the bears can also plunge into winter sleep, but not every year and not for long. The need for hibernation as such disappears, since the main food of polar bears does not depend on the season. They feed mainly on seals, which are available to the polar bear in winter, when the ice is very strong. In summer and spring, the only salvation for these animals is fish and carcasses of dead whales. Sometimes they have to starve for several months. With prolonged starvation, polar bears observe such an unusual phenomenon as sleep on the go. This state resembles the period of hibernation in ordinary bears, only very shallow. In the blood during this period, the concentration of urea in the blood drops significantly. As soon as food is found, the urea level will rise to the required level and the polar bear will become alert again.