Polar bear fur is transparent. Scientists have uncovered the secrets of polar bears

Polar bears are one of the most amazing animals that have ever roamed our planet. The mere fact that these magnificent creatures manage to survive in the cold deserts of the Arctic is almost unique.

Everyone knows that polar bears are distinguished by their strength, endurance and beauty, but not everyone is aware that they are, in addition, very smart and resourceful animals.

In addition, polar bears are the largest and strongest of all bears and also the most recognizable and popular. Unfortunately, polar bear populations are currently declining and endangered due to global change climate.

Here are amazing little known facts, which will help us solve all the riddles and learn all the secrets of these amazing animals.

Males can weigh a ton

An adult male polar bear typically weighs between 350 and 550 kilograms, that is, about half a dozen healthy, strong males. The largest polar bear ever recorded was a male weighing exactly one ton.

Unlike males, females weigh two to three times less, up to 300 kilograms. The cubs at birth are very small, bald and weigh less than a kilogram.

Hibernation - no!

These unique animals remain active all year round, despite the lack of food. Females winter in snow dens with their cubs. They prefer to dig dens in old snow, and not in freshly fallen snow. Some females build a den with several rooms and even a ventilation system. While the females are in the den (January to March), they do not eat, drink or produce waste.

They can slow down your metabolism

Since the optimal habitat of polar bears turns into a snowy desert with no food for several months, they can fast longer than any other representatives of the animal world.

If a polar bear doesn't eat for 10 days, it can slow down its metabolism until it catches its prey. Bears survive on fat stores (when food is plentiful, they prefer to eat only fat). However, warmer temperatures are making it harder and harder to find food, forcing bears to resort to cannibalism.

Polar bears don't have white fur

Although they look white, their fur is actually colorless, translucent. Each hair is a kind of tube filled with air. It looks white because, like everything transparent, it reflects visible light. For example, snow. It is also not white, but transparent.

Skin covering polar bear under black fur to better absorb and retain heat.

To those representatives of the animal world who perceive only visible rays of light (that is, to us), it seems that the bears merge with the snow. But reindeer, which occasionally becomes a victim of a hungry bear, sees in ultraviolet radiation, which helps him to discern a lurking predator.

Sometimes the fur of polar bears turns dirty yellow or even green. The yellowing is due to the age of the bear or dirt while green color caused by algae that can grow on polar bear fur in unnaturally warm and humid environments.

Among other things, the fur of polar bears is oily, which allows them to not get wet while swimming and quickly shake off the water.

Paws of polar bears

The polar bear is so strong that it can kill an animal with one blow of its huge paw.

These massive and strong paws help polar bears swim. And it is worth noting that polar bears are excellent swimmers: their hind legs help them stay afloat, and their front legs help them move forward. They can swim up to 160 kilometers at a time.

Their paws are equipped with special stiff wool pads, which allow them not to slip on the ice, and also to step almost silently, sneaking up on prey.

By the way, during the hunt, the female cubs are forced to remain absolutely motionless. If they break the rule, mom gives them a slap in the face with that very powerful paw.

Supernaturally sensitive nose

These amazing animals have an unusually keen sense of smell, which they use to hunt.

A polar bear can detect prey by following a trail left on the ice at a distance of 30 kilometers.

Most polar bears could be extinct by 2050

Polar bears rely on ice to feed successfully. Scientists predict that global warming will melt the sea ice enough that the result will be the extinction of two-thirds of the world's polar bear population by 2050.

The bears will be forced to swim too far, expending the energy they need to save for hunting and simply for survival.

Delayed fertilization

Bears mate from March to June, but the egg is not fertilized until September. The time of fertilization depends on the state of health of the female and on environment. Most often this occurs between September and November.

The delayed fertilization process ensures that polar bear cubs are born to healthy mothers at a time when conditions for survival are optimal. Female polar bears do not produce offspring before age 4-5 years.

Climate change brings hybrids

Warmer and long summer pushes some animals to expand their habitat. New species enter new territory and come into contact with previously isolated animals. Sometimes meetings of new neighbors are especially friendly.

Over the past decade, scientists have documented several hybrid offspring of polar bears and grizzly bears. Researchers have predicted that the Arctic will become a breeding ground for species as extensive and abrupt ice melt opens previously blocked areas.

Polar bears are more likely to overheat than freeze

Even without the black skin underneath transparent fur absorbing heat, polar bears have other tools to survive in the cold Arctic.

They have two layers of fur and a thick layer of fat that do an excellent job of insulating themselves, and their small ears and short tails and small snouts help minimize heat dissipation.

It sounds a little paradoxical, but polar bears are more likely to overheat than freeze during arctic frosts. They overheat very quickly when running. That is why they tend to move slowly and try not to overexert themselves.

It is believed that with global warming and the melting of the Arctic, the polar bear may disappear. But the real threat to the life of the strongest and most intelligent predator on earth is not the climate at all.

“I have never had so much fun before as I get from working with a polar bear,” says Nikita Ovsyannikov, deputy director of the Wrangel Island nature reserve. - This is an absolutely magical beast, in twenty-two years there has not been a moment when I got tired of watching him. You look at him every time enchanted, like a child.

Ovsyannikov wears a T-shirt with a polar bear covering its muzzle with its paws and the inscription "Rethink!". Few people in Russia know the habits, ecology and lifestyle of polar bears better than Nikita.

The polar bear is really mesmerizing. This is the largest land predator in the world and the only one that has adapted to live in the severe arctic cold. Of course, there are also other predators like arctic fox, wolf and wolverine, but they live in many places, and the polar bear is ideally suited to the northernmost latitudes. The bear is the only inhabitant of land that can spend his whole life in the sea: he swims and hunts perfectly in the water, and not land, but an ice floe, is best for him to rest. Therefore, it is classified as a marine mammal (“mormlek”) along with pinnipeds and cetaceans. It is protected from hypothermia by a thick layer of fat (unlike people, the fatter the bear, the healthier it is) and thick fur. The fur coat of a polar bear consists of hollow hairs that hold heat well. Sometimes in the summer you can see a bear with a green tint, which means that microscopic algae have wound up in the cavities of its wool.

In terms of intelligence, polar bears are hardly inferior to primates: they are able to solve complex problems, navigate in three-dimensional space and have excellent memory. Each animal, like a person, has its own bright personality. Ovsyannikov says: “Cape Blossom on Wrangel Island used to be a traditional place for bear parties, and it was convenient to watch them there. When you look at dozens of bears day after day, you begin to distinguish their character, they are all different, just like us. And they have a very rich facial expressions. One geologist once told me, they say, brown bears dead face. I answer: did you see your face when you met them? Bears would also say that a person always has the same expression and bulging eyes.

Over the years of observation, Ovsyannikov noticed and described another unique property of bears - their great social plasticity. They are not at all solitary predators, as was believed, and although they do not gather in packs, they can coexist, especially if there is enough food for everyone: “I have seen up to twenty-two bears around a seal carcass. They can growl and push while they share a meal, but they do not reach serious conflicts. There is a strict hierarchy: adult males eat only tidbits - fat, leaving meat on the bones of younger cubs.

Polar bears are not individualists, although they do not need to cooperate. In contrast, for example, from lions, they hunt on their own, but they cut the prey together. Moreover, they can share even with strangers who come from other places.

Healthy lifestyle

In the spring, the season of love begins, and adult bears become pregnant every three years. More often it is impossible because of the unusual duration of the process: after intercourse, the fertilized egg divides only a few times, but does not attach and does not develop for almost half a year, until the she-bear lies in the den for hibernation. The bear devotes the rest of spring and summer to hunting, gaining weight and preparing for hibernation. In September-October, she comes out on land, climbs the mountains, finds a quiet place and digs a lair in deep snow.

When a bear goes into hibernation, her pregnancy begins to develop. In January, she has cubs - blind, almost naked and weighing only 500 grams. For the first three months, the she-bear feeds and licks them without getting out of the den. In March-April, the cubs, grown up to 3-5 kilograms, crawl out into the light, at first they play near the den, and then the mother takes them to the ice. Polar bears grow up very slowly: usually a female bear leads her offspring for two and a half years. This time she feeds them and teaches everything she can. However, even an adult three-year-old bear feeds for the first years on what is left of more respectable adult relatives. Males do not sleep in winter and prefer to stay on the ice all year round if conditions permit. However, this possibility appears less and less. “According to my own observations, the climate has changed a lot, there has been more precipitation and fog, and most importantly, less ice- says Ovsyannikov. - Therefore, the bear is increasingly coming to the ground. The weather has become less predictable, winter thaws have appeared.”

Bears prefer to eat marine mammals, but in famine years they do not disdain smaller prey like arctic foxes and lemmings, and even carrion. And about how bears steal food from polar explorers and meteorologists, a rich folk epic is composed in the North.

Due to warming, life expectancy on the coast is increasing and populations are declining, especially those that live further south than others. In addition, it happens more and more often that a female bear, left on an ice floe far from the ground, is forced to lie down in a den right there, and this is quite dangerous, since the ice moves and breaks. How the climate in the Arctic will change, no one knows for sure, but according to the most confident scenario by the end of the century mean annual temperature can rise by 4–7 degrees, and the ice-free period will increase to six months. By itself, this may not be so scary. According to paleontological reconstructions, the polar bear evolved from the brown one about 120,000 years ago, and according to new genetic data (analysis of the mitochondrial DNA of species), even earlier, about 600,000 years ago. Thus, the polar bear survived at least six global warming antiquities.

In addition, two cases of crossing a polar bear with a brown bear have already been described. A few years ago, a hunter in Canada killed a polar bear, which, upon closer examination, turned out to be unusual, with dark glasses around the eyes and an unusual body structure for this species. Genetic analysis has shown that it is a hybrid of a polar and brown bear. it different types, but they can mix and, importantly, their offspring can also give birth to children. “Everyone repeats like a spell that with the melting of the ice, the bear may disappear,” says Ovsyannikov. - But they are too smart, ecologically and socially plastic, I am sure that they will be able to adapt to changes. Of course, it is more convenient for a bear to live and hunt on ice, but it also endures long periods without ice on land, where, if necessary, it feeds at the very least and does not die out. If it is not destroyed by man. And this is the real threat."

The Real Threat

There are 19 geographical populations of the polar bear in the world, of which three live in Russia: these are the Chukchi-Alaska population, the Laptev and the Kara-Barents Sea. Satellite tagging has shown that they are conservative and prefer to follow known routes.

It is almost impossible to estimate the size of the population, because every year the main habitat of the bear - the shelf ice - disappears and some of the animals move further north, and some go to mainland. On the IUCN/SSC Polar Bear Specialist Group website, you can find a rough estimate - from 20,000 to 25,000. “This is taken from the ceiling, in reality there cannot be so many now,” says Nikita Ovsyannikov. - Moreover, it is not known how many bears are left in Russia. In the 1970s, there was the last attempt to estimate the size of the Chukchi-Alaska population, then it was about 2000–5000 individuals. In fact, now there cannot be more than 1500-1700. Even in the early 2000s, we observed much more animals on Wrangel Island than now, tens and hundreds of animals over an area of ​​two kilometers. Today, according to my observations, the density reaches 38 animals per hectare. Now we can meet no more than 60–70 bears on Wrangel, and in the 1990s there were 300–400.”

In 1973, five Arctic states - the USA, Canada, Denmark, Norway and the USSR - signed an agreement on measures to preserve the polar bear population. According to it, hunting was allowed only to the indigenous peoples of the Far North, since it is believed that this is their traditional trade. Norway subsequently introduced a complete ban on hunting. And in the USSR, it was first installed in 1957. In Alaska (USA), Canada and Greenland (Denmark), quotas are still issued to indigenous people. This is one of the benefits that the government gives to the endangered natives as compensation for the difficult colonial past. “I have repeatedly told my American and Canadian colleagues that they are paying with a bearskin for the destruction of small peoples,” says Ovsyannikov. "It's cynicism and politics."

In America, Canada or Denmark, wealthy people often come to the North, negotiate with the locals, treat them to whiskey and take one with them on hunting trips to protect themselves from the huntsmen. And in Canada, Aboriginal people are officially allowed to sell their quotas. As a result, an attempt to preserve the traditions of small peoples turns into an entertainment industry in which animals die.

Despite the wonderful laws, bears are shot in Russia no less than in other countries - because of poaching. By law, you can only shoot a bear if it poses a danger to life, but in fact, many locals shoot out of sheer excitement, barely seeing the animal, in order to later present it as self-defense. Buying the skin of a polar bear in RuNet or a trophy store is not difficult. Around the world, 300-400 animals are shot annually, and a third of them are cubs under three years old. At this rate, it is possible to exterminate the polar bear within 20-25 years.

Studying polar bears in Canada and the United States is largely about estimating numbers to decide how many quotas to give out each year. To do this, use the capturerecapture method (“catch and recapture”). To capture a bear, it is tracked from a helicopter, immobilized with a telazol syringe, then the petrified animal is examined and samples are taken. So you can set the floor, measure the weight and size. To find out the exact age, a tooth must be pulled out from the beast. Along the way, you can take a tissue sample for a biopsy or genetic studies, as well as put on a collar with a tag for satellite tracking, so that you can then study migrations. At first glance, this method allows you to collect a lot of objective data. But in reality, this method of study has more disadvantages than advantages, Ovsyannikov insists. "This approach says nothing about the natural behavior of the bear," he says. “Moreover, after experiencing a severe shock, a bear may behave inappropriately, and observation of it leads to erroneous conclusions. If you are studying the natural biology and ecology of bears, then you should not bother them, much less torture them. Americans collect data year after year, but know nothing about the habits or lifestyle of the bear. They only see him running away from the helicopter and then writhing in agony.”

The Joy of Human Communication

Ovsyannikov himself studies the polar bear in exactly the opposite way. It is an adventure for him: to live close, but not to disturb or frighten the beast. Only in this way can its natural life be explored. Ovsyannikov started his project in 1990. He moved to Wrangel Island to spend the whole year there. Lived alone most of the time last years- with his wife Irina, who studies snowy owls and arctic foxes. Today Ovsyannikov comes only from spring to autumn. “We survey key polar bear habitats every year, covering thousands of kilometers on an ATV,” he says. - Often we spend the night in primitive beams, which are also broken by bears, so there is nowhere to spend the night. But you can see them up close. On my Wrangel, I could take into account all 200-300 bears, because I already know where they are most likely to be found.

This method of observation allows you to accumulate unique data on the size, composition and average age of the population, and most importantly, on the behavior and social organization - how bears interact with each other, hunt and live in general, as well as how they react to human activity and what are the factors in their behavior. life limiting population growth. The job of the animal sociologist is to assemble the pattern of behavior, like a mosaic, from the individual events that can be recorded. The more you observe, the clearer the picture emerges and the clearer what gaps remain to be filled. For example, if you need to understand how a she-bear with cubs hunts, you need to find a place where this is likely to happen and patiently wait for the event.

“When you live among animals, you need to strike a balance: on the one hand, you can’t disturb them, on the other, it’s impossible to hide or become invisible,” explains Ovsyannikov. - And arctic foxes, and owls, and other animals are always aware that you are nearby. Therefore, you need to build relationships with animals so that they are familiar with you and treat you as part of the landscape, which is present, but not annoying. You need to show that you are such an aggressive monkey, which, however, is harmless if left untouched.

Most effective method explain this to the bear - make noise, but do not scream. Sharp, for example, metallic, sounds frighten the beast, and a lively voice, on the contrary, is usually inherent in a frightened victim. Ovsyannikov uses a method that requires special courage: he quickly and aggressively goes straight at the animal, stamping heavily and waving his arms. Bears learn quite quickly and soon learn that it is better not to approach a person. “True, new animals appear in the population all the time, with which it is necessary to build relationships anew,” says Ovsyannikov. - If a problem animal appears, it can be seen immediately, it is so brutal and self-confident, it is immediately clear that there will be difficulties with it. So of course universal recipe no, each bear needs to be looked at separately.”

Polar explorers love stories of friendship with tamed bears. Usually, however, friendship begins with the murder of the mother: cubs without a mother are completely helpless and die of hunger. If you pick up such a bear cub and feed it, it can grow tame. One hunter picked up a polar bear cub, named Aika and kept it in his apartment in Norilsk, and when the bear grew up, he transferred it to the zoo. On Schmidt Island, another man tamed a bear, named it Masha, and fed it by hand. On Kotelny Island, meteorologists are still Soviet times raised a bear named Umka, who lived under the porch like a dog. “All these games do not lead to anything good either for bears or for people,” says Ovsyannikov. - The bear takes a person for his own and communicates with him on an equal footing. At any moment, if he doesn’t like something, he can hit with his paw or bite, as is customary with them. And for a person, even a light slap by a bear’s paw can be fatal. This happened to one German trainer who had the most tender relationship with the beast, but at some point he killed her, according to eyewitnesses, completely unintentionally. Than trying to establish unnatural relationships, it would be much more useful if people stopped disturbing bears, and even more so exterminating them. That would be true friendship."

Photo: HEDI AND HANS-JURGEN KOCH EAST NEWS (x10)

We have already examined in detail and were surprised. Now let's take a closer look at the well-known Polar Bear and in more detail.

Polar bear- most A big bear, he is the most large mammal order of carnivores in the world. The body length of an adult male can be up to 3 meters, and the mass can reach a ton. The largest representatives of the polar bear were seen along the shores of the Coastal Sea.

The polar bear is listed in the IUCN Red Book and the Red Book of Russia. Bear hunting is allowed only to the indigenous population of the North.

The skin of a polar bear is black, like a brown bear. But the color of the skin is from white to yellowish. Also, the fur of a polar bear has a feature: the hairs are hollow inside.

The bear seems clumsy due to its size and dimensions, but this is only an appearance. Polar bears can run fast enough, and even swim well. Bear north passes a day from 30 km. The bear's paw is unique. No deep snow can stop a bear, thanks to its size of feet and columnar legs, even compared to other polar animals, it very quickly and deftly overcomes any snow and ice obstacles. Cold tolerance is amazing. In addition to hollow hairs, the polar bear also has a subcutaneous layer of fat, which in winter can be up to 10 cm thick. Therefore, a white bear can easily overcome up to 80 km in icy water. In the summer, a bear can even swim to the mainland on an ice floe, then it is euthanized and sent back by helicopter.

In Russia, polar bears are found on the coast of the Arctic Ocean, in Greenland and Norway, Canada and Alaska.

The main food of the polar bear is seals. One bear eats about 50 seals a year. Catching a seal, however, is not easy. The northern bear can watch for prey at the hole for hours, waiting for the appearance of a seal on the surface. After the seal has surfaced to take a breath of air, the bear instantly beats the prey with its paw and throws it onto the ice. The predator eats the skin and fat, prefers to leave the rest, although in winter, in case of hunger, the bear eats the whole carcass too. The bear is often accompanied arctic foxes, who get the remains of the seal. Polar bears also do not disdain carrion, the bear smells the smell of prey at a distance of several kilometers. For example, beached whale will definitely become a meeting place for several bears. 2 bears or 3 bears may not share food, then there is a skirmish. How many bears can meet is unknown. That is why a bear can enter the territory of human habitation. More often, of course, this is simple curiosity, although an evil hunger can drive the beast into hopeless situation. Although the bear may be a vegetarian, they like cereals, lichens, sedges, berries and mosses.

Spring is the time of paradise for bears. Young marine animals are born, which, due to inexperience and weakness, do not offer proper resistance and often do not even run away.

The polar bear has an incomparable resistance to cold. Its thick long fur consists of hairs that are hollow in the middle and contain air. Many mammals have this protective hollow hair, an effective insulator, but those of the bear have their own characteristics. Polar bear fur retains heat so well that it cannot be detected by aerial infrared photography. Excellent thermal insulation is also provided by the subcutaneous layer of fat, which reaches 10 cm in thickness with the onset of winter. Without it, the bears would hardly be able to swim 80 km in the icy Arctic water.

By the way, polar bears are the only large predators on Earth, who still live in their original territory, in vivo. This is largely due to the fact that seals, their favorite and main food, live on drifting ice in the Arctic. There are approximately 50 seals per bear per year. However, hunting seals is not easy. The state of the ice changes from year to year, and the behavior of seals is unpredictable. Bears have to walk thousands of kilometers in search of the best places for hunting.

In addition, the hunt itself requires skill and patience. The bear spends hours guarding the seal at the hole, waiting for it to come up to get some air. He instantly strikes with his paw on the head of a sea animal that has emerged from the water and immediately throws it onto the ice. First of all, the predator devours the skin and fat, and the rest of the carcass - only in case of great hunger. A bear hunting a seal is usually accompanied by one or more arctic foxes, eager to take advantage of the remains of dead animals. White bears themselves do not disdain carrion, thus compensating for the lack of seal fat and meat. The owners of the ice kingdom can smell carrion for several kilometers. And if suddenly a whale, having fallen into shallow water, dries up and dies, a whole company of polar bears, always hungry, will immediately come running from all sides.

Hunting for seals is not at all easier. At the slightest danger, shy seals dive under the ice and emerge in another hole for breathing. And the bear vainly rinses his face in ice water. But in the spring, a fertile time comes for the bear - cubs of marine animals are born who have never seen a polar bear and therefore do not realize the danger. But here too clubfoot bear you have to show miracles of ingenuity. In order not to frighten off the cubs, the bear has to be very careful, because even the slightest crunch can betray its presence and deprive it of food.

Difficulties with the extraction of food are exacerbated by climate change on Earth. Due to the warming of the climate, the ice in the bays begins to melt earlier than usual, the summer is getting longer every year, the winter is getting milder, and the problems of polar bears are becoming more acute. Summer, in general, is a difficult time for polar bears. There is very little ice left and it is almost impossible to get close to the seals. Over the past 20 years, the hunting season for polar bears has been reduced by two to three weeks. As a result, the weight of animals has decreased: if earlier the male weighed about 1000 kg, now, on average, 100 kg less. The females also lost weight. This, in turn, has an extremely negative effect on the reproduction of the population. Increasingly, only one bear cub is born to females ...

However, polar bears suffer not only from warming and shortening of the hunting season. In the recent past, the polar bear was an important target for hunting. Fur and bear paws, which are essential component popular and expensive oriental soups, pushed the members of the polar expeditions to the ruthless extermination of this beautiful beast. The profits from such a business are so great that the international black market continues to thrive, despite all attempts to stop it. The struggle in this area has reached the same intensity as the fight against drug smuggling.

In July, many of the polar bears that traveled with drifting ice move to the coasts of the continents and islands. On land, they become vegetarians. They feed on grasses, sedges, lichens, mosses and berries. When there are many berries, the bear does not consume any other food for weeks, eating them to the point that his muzzle and buttocks turn blue from blueberries. However, the longer the bears starve, forced to move to land ahead of time from melting ice as a result of warming, the more often they will go in search of food to people who have been actively developing the Arctic in recent decades.

It is difficult to answer the question whether a meeting with a polar bear is dangerous for a person. Sometimes bears attacked people out of curiosity, quickly realizing that they were easy prey. But most often, tragic incidents happen on campsites, where bears are attracted by the smell of food. Usually the bear goes immediately to the smell, crushing everything in its path. The situation is complicated by the fact that the animal, in search of food, tears to pieces and tastes everything that comes across to it, including people who have turned up by chance.

It should be noted that bears, unlike wolves, tigers and other dangerous predators, mimic muscles are practically absent. They never warn of impending aggression. By the way, circus trainers claim that because of this feature, it is most dangerous to work with bears - it is almost impossible to predict what to expect from them in the next moment.

Now, thanks to the efforts of Greenpeace, they try not to kill bears wandering into the city in search of food, resorting to temporarily sleeping shots from a special gun. The sleeping animal is weighed, measured and recorded. A colored tattoo is applied to the inside of the lip - a number that remains for the whole bear's life. Females, in addition, receive a collar with a miniature radio beacon as a gift from zoologists. The euthanized bears are then transported by helicopter back to the ice so that they can continue their normal lives in natural environment a habitat. Moreover, females with cubs are transported in the first place.

The world for the polar bear is limited by ice fields, and this primarily determines the features of its behavior. Judging by the animals kept in captivity, this bear, in comparison with the brown one, seems less quick-witted and not so dexterous; he is less trainable, more dangerous and excitable, and therefore it is relatively rare to see him in the circus arena. True, he is characterized by some “straightforwardness” in actions, due to a rather monotonous lifestyle, narrow food specialization, and the absence of enemies and competitors. But even a short time to observe this beast in a natural setting is enough to be convinced of the high level of his psyche, his exceptional ability to assess conditions natural environment, including the quality of ice, adapt to them and, depending on them, flexibly change hunting tactics, find the easiest and most passable paths among heaps of hummocks, confidently move through young, fragile ice fields or areas of ice, replete with cracks and leads.

The power of this beast is amazing. He is able to drag and lift up the slope the carcass of a walrus weighing over half a ton, with one blow of his paw to kill a large bearded seal, which has almost the same mass as his, and if necessary, easily carry it in his teeth a considerable distance (a kilometer or more).

Polar bears are eternal nomads. Ice carries them over great distances. It often happens that even such experienced "travelers" are in distress. So, animals that have fallen into the zone of the cold East Greenland Current are carried on drifting ice along the southeast of Greenland, and in the Davis Strait the ice is melting, and most polar bears, with all their dexterity, die.

It would seem that living in the deserted polar expanses, the polar bear should not have to suffer from a person. However, it is not. The Arctic is already fairly settled. Sailors, St. John's wort, people of other professions are now constantly meeting with polar bears, and these "contacts" do not always end favorably for huge, but very curious and generally harmless animals.

Yes, and the very biology of the beast has "weak" sides. During the mating season, the male has to travel great distances to find a female, and often endure a battle with a rival. Often searches are not crowned with success at all and families are not formed. Bears bring offspring (one or two cubs) every two years and become sexually mature only at the age of about four years.

The availability of food (seals and fish), suitable breeding sites, and the absence of human disturbance are the main conditions for the existence of polar bears in the Arctic. But there are not so many places like this at first glance. The unique "maternity hospital" of these animals is Wrangel Island. In addition, polar bears make lairs on the northeastern islands of Svalbard, on Franz Josef Land, in the northeast and northwest of Greenland, in the southwest of Hudson Bay and on some of the Arctic islands of Canada. The main territory of the Arctic, in fact, is not suitable for habitation, and even more so for reproduction of this species.

All pregnant female polar bears spend the winter in snowy shelters, relatively similar in design and located, with rare exceptions, on land; everywhere in the Arctic, they enter and leave their dens at almost the same time. The physiological state of animals in dens is similar to that of brown bears, i.e., this is a shallow sleep or torpor with some decrease in body temperature, respiratory rate and pulse, but not hibernation (as, for example, in marmots, ground squirrels, etc.) . Apparently, at the beginning of winter, the she-bears lying in the dens are more active than in the middle of winter, although in the spring in most dens one can see traces of the burrowing activity of females of different age.

The question of the winter activity of males, barren females, and young individuals is not clear enough. Obviously, in a significant part of the range, especially in the south of the Arctic, they are active all year round, with the exception of periods of strong snowstorm, from which the animals hide among hummocks or coastal rocks; finding here before. a fairly deep layer of snow, they even dig shallow shelters in it. With the end of the snowstorm, the bears leave such shelters and continue to roam and hunt.

In the high latitudes of the Arctic, especially in places with a harsh climate, frequent and strong winds, and possibly where the animals experience great difficulties in feeding, most of them relatively regularly lie down in dens. On the northern coast of Greenland, 90% of all animals spend the winter in shelters, in the northern part of Baffin Island - 50% and in the south of Greenland - 30%; in general, 70-80% of all bears overwinter in shelters throughout the range, and old males lie down in shelters earlier and leave them earlier.

In the Canadian Arctic, male polar bears use the shelter from early August to late March (most often in September, October and January); young, as well as females with one-year-old cubs, were met here in shelters from early October to early April. The state allocates funds for buildings made of laminated waterproof plywood, which greatly helps the animals.

In the north Taimyr Peninsula(the area of ​​Cape Chelyuskin) all animals spend the winter in dens, but the duration of their stay there is different and depends on sex, age, and whether the female is pregnant or barren. For the shortest period (at the latest 52 days - from mid-December to early February), young bears lie in shelters in the north of Taimyr; almost the same number of adult males are in them. Females with underyearlings spend 106 days in dens, barren females - 115-125, and pregnant she-bears - 160-170 days.

There is information in the literature about encounters in the dens of male polar bears on Franz Josef Land, in the east of Taimyr, in the Kolyma Territory, etc., although everywhere here animals of various sex and age categories were observed and hunted outside the den, which means that they were active throughout the winter. The dens of such animals (obviously, the shelters of barren females, young bears) are often located on sea ​​ice and in terms of structure (shape, size) are more diverse than the dens of pregnant bears. It is also obvious that the terms of their use are relatively inconsistent.

The polar bear is the world's largest terrestrial carnivore, living in the Arctic: in remote northern regions Greenland, Norway, Canada, Russia.

And although polar bears traditionally look white, surprisingly, their fur is devoid of white pigment, in fact it is translucent, and its skin is black. So why is the polar bear white? The answer to this question is given by scientists' research on what the polar bear's fur consists of, as well as the study of optical phenomena that affect the color of the fur of this animal.

: The polar bear is the largest land predator on Earth. The length of the animal is about 3 meters, weight - up to 1 ton.

What is polar bear fur made of?

The polar bear's coat contains two layers of hairs: an outer protective layer consisting of long (5-15 cm) guard hairs; and a dense insulating undercoat, the hairs of which are shorter and finer than in the protective coat.

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The skin of the polar bear is black, and the fur is translucent

Properties of protective hairs:

• translucent;
• hollow, i.e. empty inside;
• rough, narrowed (gradually reach the base);
• contain particles that scatter light;
• contain salt particles;
• are made up of the protein keratin.

The translucent hairs of the bear's fur appear white also because of the density of the animal's fur.

Influence of optical phenomena

Wool northern bear translucent, but due to the properties of the protective hairs that are involved in creating the optical effect, these animal fur appears white. From an optical point of view, the reason why a polar bear appears white is due to the effect of light on the animal's hairline.

Luminescence

Exposure to light causes a reaction known as luminescence

When the sun's rays fall on the fur of a polar bear, some of this light falls into a kind of trap in the hairs. This light energy is reflected inside the hollow part of the hairs, causing a reaction that is the emission of light - luminescence. This happens every time a beam of light comes into contact with an animal's fur.

The luminescence is accelerated by light scattering particles in the hairs, which destroy the light beam. When light hits a light-scattering particle, it breaks up into more rays that move in different directions. Light scattering particles are found both on the inner surface of the hairs and on the outer. Scattering of light causes more white to appear and be further radiated by the animal's hairline. Thus, the translucent bear fur reflects sunlight. This is the reason why polar bears are especially bright in direct sunshine. The brighter the light, the more light is reflected by the polar bear's translucent fur.

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Salt particles

sea ​​salt particles

Polar bears spend a lot of time in the water, which is why Latin name these representatives of the bear family ursus maritimus, which means "sea bear". Polar bears collect salt particles while swimming or staying near a salty area. sea ​​water. Salt particles along the rough surface of the wool also act as light-scattering particles, which increase the amount of light rays and enhance the luminescence.

ultraviolet light

Ultraviolet light in the spectrum of optical radiation

When the sun shines on a polar bear, ultraviolet light travels along the protective hairs to their base and penetrates the animal's dark skin. When ultraviolet light hits the skin, it causes a whitish color due to fluorescence (the ability to give off absorbed energy as cold light radiation). Fluorescence is a type of luminescence. Thus, ultraviolet radiation also causes the white color of the bear's coat.

Interesting fact: The ultraviolet rays, which are carried through the translucent hairs, give the polar bear's fur its insulating properties.

Keratin

Keratin is a common natural protein found in skin, nails, and hair. Like humans, bear hair contains keratin. Protein molecules of keratin give off a whitish color, which further contributes to the appearance of a white coat in a bear.