The habitat of this species is quite vast and includes the circumpolar area that is bordered to the south by the northern coasts of continents and by the southern tip of the drifting ice in the north. Over the last several centuries the territory where this species is common hasn’t changed at all, except for seasonal changes at the southern border of the habitat.
The polar bear is common on Russia’s territory from Chukotka to the Frantz Josef Archipelago and Novaya Zemlya and they sometimes reach Kamchatka on drifting ice floats. Researchers have noticed that it moves up to 500 kilometers into the continent.
Humans met this very interesting animal quite a long time ago. Northern Asia learned about it back in the Paleolithic Age and the North of Europe in the Holocene. Polar bears were known in Ancient Rome as well. Scientists have found references to this animal in written documents that date back to the 1st century A.D. Notes found in the archive of Japanese Emperors witness that even in the 7th century A.D. polar bears’ hides started appearing in Manchuria and Japan. It is probable that the animals reached the shores of the Far East on drifting ice floats.
880 A.D. became the year when Europe was introduced to polar bears. A couple of bear cubs were brought from Norway to Iceland and in 1774 a British zoologist, Constantine Phipps, accurately described the animal in scientific literature, which is how the animal got its Latin name.
So, what does this great animal look like? The polar bear is the largest animal in its whole species. The weight of males is up to 800 kilograms and their length is up to three meters, while the shoulder height is up to a meter and a half. Naturally, females are much smaller and much lighter.
The body of a polar bear is oblong with a substantial rear that narrows a lot to the chest. The animal has a narrow elongated head that is flat on top with a somewhat low forehead. The head is set on a thick neck that switches into sloping shoulders. Its body is supported by strong paws. The polar bear’s soles of its paws are longer that those other representatives of its family and they are covered in fur which protects the paws from frostbite in conditions of perpetual frost. The toes up to the middle of their length are connected with flippers and are equipped with strong bent toenails.
The whole body of the predator is covered in thick fur. Despite common opinion, it is not white, but transparent because the fur does not contain any pigment. The fur of the young of the species has a silver tone and by old age, due to eating greasy food and the impact of sunlight, it becomes yellowish. Single fur hairs are empty inside, similar to optic fibers and easily conduct sunlight. The bear’s skin is black which helps them to store the maximum amount of the Sun’s energy. The last level of protection from the cold is a layer of fat. A polar bear hunts in icy water as well, which is why the fat stored under the skin is just a necessary requirement for survival in this severe climate.
The brain of this species is more complex than that of any other predator on the planet. The structure and placement of grooves and convolutions and the general outlines are more like the brain of web-footed mammals. Bears have sharp eyesight and a phenomenal sense of smell. The structure of the gastrointestinal tract is characteristic of predators. Unlike other types of bears, polar bears have shorter intestines and a huge stomach capable of holding a whole seal.
The maximum life expectancy of a polar bear is 25-30 years, though a case is known when a female bear in a Detroit Zoo lived for more than 45 years. However, in their natural habitat the average life expectancy is 18-19 years. The percentage of mortality rate varies from 20-30% for bear cubs and up to 8-16% for adult species.
The life of the polar bear directly depends on the drifting and sea shore ice where it spends most of its life hunting seals. They also live in hiding places, i.e. small coves at the shore where sea currents break up the ice and open the water up.
In winter, bears most often live on the shore area closer to continuously open stationary ice holes. This provides them with regular access to water and therefore to food. If the ice situation becomes difficult, bears migrate to areas where the ice has broken down. In summer, their favorite place for life and hunting is the southern border of the ice mass.
The polar bear spends its whole life on the ice. If he ever does make it onto the continent, his usual trips there are so short that they can be ignored. The only place where polar bears often show up on the shore are the Northern islands — Greenland, Labrador, Spitzbergen, Frantz Josef Archipelago and Novaya Zemlya.
Other than humans, polar bears don’t have any natural enemies. These predators are not afraid of humans either. No other species among animals would be brave enough to challenge this huge killing machine. However, humans are doing everything in order to persistently reduce the numbers of this most rare species by shooting the animals for hides and polluting their habitats with oil products and pesticides. It has reached such a state that polar bears recently were put on the international endangered species list, and not such a very long ago the population started restoring itself and the number of animals grew.
Very recently all of the countries in the Arctic belt made a commitment to preserve and increase the population of this great animal. Ministers of a number of countries made decisions during an international forum that would help to conserve polar bears.
Polar bears are 100% predators. They obtain food by active hunting, at the same time their field is narrow. Their diet consists mostly of seals and fish. With seals bears first of all eat the skin and the subcutaneous layer of fat and they will only eat the body itself when they are very hungry. Every bear eats up to fifty seals per year, the majority of them are ringed seals and bearded seals.
Polar bears catch seals by ambush. They hide near ice holes and wait until a seal gets his head out of the water. At the moment when the unsuspecting animal reaches the surface, a terrible blow by a powerful paw immobilizes it and throws it on the ice. Usually bears eat up to 8 kilograms of meat at a time, but there were cases noted where their one-time portion would go up to 20 kilograms.
Bears have to catch fish in the water. They quite good swimmers and divers, which is why a hunting trip is very often successful. Two types of outcomes are possible: the bear either just runs after a fish in the water and immobilizes it with its paw, or puts the prey into a crevice between ice floats where it is very easy to get at. Polar bears attack ground animals very rarely, only in those cases when they are very hungry or when there are no usual sources of food around. An analysis of the contents of the stomach of a polar bear allows us to confidently state that sometimes it also eats berries, moss and other plant foods.
After the future victim has been found, a bear flattens himself on ice, starts crawling and carefully sneaks up on it. Every time the victim starts to turn around, he freezes and waits this moment out in complete immobility. The nose and eyes that could give him away with their black color are covered up by the hunter’s paw.
Sometimes polar bears attack seals from the water as well. Seals don’t usually lie far away from the ice hole so that whenever they feel the first sign of danger they can quickly dive into the safer water. Polar bears know this and try to find these sites. After that, they noiselessly dive and swim under the water to their targeted victim. A sharp hurl from the depths at an unsuspecting, clumsy seal on the shore does not give any chance to its victim. This hunt in the majority of cases is successful for the predator.
If there is an opportunity, a polar bear doesn’t mind picking up dead fish that was thrown onto the ice during a storm either. The same is true for eggs and chicks of sea birds, seaweed and other creatures that the hunter sees on its way. Another non-standard source of food for a bear has become people’s storehouses which people set up even in such wild and unwelcoming places as polar bears’ habitats. Besides, as a bear lives not far from human hunting areas, he will be pleased to eat seal bodies that are skinned, trimmed of fat and left by hunters.
Polar bears have an extremely high level of mental organization. An amazing ability to immediately evaluate the current situation and an ability to orient itself in any area make them a very dangerous opponent. Moving around tough terrain, often during polar nights or storms, it will never get lost and will continue going in the direction it needs.
The well-developed sense organs allow a bear to notice its prey even from far away. It often goes up icy mountains and looks around from the top, searching for seal rookeries. It has such a well-developed sense of smell that it can pick up the scent of a seal or of fried meat at a distance of several kilometers. Its excellent sense of smell and eyesight in have many ways determined the hunting style that is typical of only polar bears. It doesn’t rush anywhere and it never changes direction, easily jumping over two-meter long cracks.
The predator feels confident not only on land but in water too. Other than good swimming ability, a polar bear manages to dive very well. Even from the height of several meters he goes into the water as an Olympic champion would, without any splash or noise.
Wide front paws with webbing are similar to paws. A polar bear is able to reach a speed of up to 5 kilometers per hour in the water and can tirelessly swim for several dozen kilometers. This is achieved mostly by its subcutaneous fat, which does not only fulfill the function of a heater, but also helps the bear to stay afloat. Other than that, the polar bear is extremely strong and enduring.
It doesn’t close its eyes in the water but follows the potential victim intently. The bear, on the contrary, closes his nostrils and small round ears in order to avoid getting water in them. A polar bear has excellent lungs and a powerful chest. The air reservoir in the lungs is such that it can stay under water for up to 5-7 minutes.
The majority of polar bears are active for the whole year and only pregnant female bears bearing babies can fall into winter hibernation. The rest of the bears climb into their lair only if a year was unsuccessful and they are starving. But that doesn’t always happen, and the period of hibernation for polar bears is much shorter than for their brown bear relatives.
A polar bear is a nomad. He constantly moves from place to place, from ice float to ice float looking for prey. Even the worst frosts are not scary for him. The only necessary requirement for its life is having an open water source nearby. If all ice holes are covered with ice, the bear starts looking for new hunting locations.
It is interesting that scientists can follow polar bear migrations only using female bears. The issue is that beacons are attached to the animals using leashes, and for males the circumference of the neck is bigger than the circumference of the head. That is why the leash just easily slides off the bear when he bends down.
Each polar bear takes up a great territory and actively protects it from its neighbors. Sometimes, however, quite a lot of bears come together during the mating season or at a whale’s body that has been thrown onto the shore. Males may be very aggressive and often get into fights over food or a female mate during the mating period.
Female mates are very quiet, enduring and calm. They often locate the lairs close to others and one time, scientists found two females who were living in one lair! They take care of their bear cubs and often take them into their families and even feed the abandoned children of others.
Females become mature at the age of four and males at the age of five or six years old. The first pregnancy for a female usually happens between four and eight years of age and the reproductive age reaches 21 years. The peak of the reproductive ability is during the period between 1 and 19 years old.
In general, bears do not have a high potential for propagation and are not very fertile. A female bear gives birth once every three years. The first time she carries one bear cub, then more often only two of them, and throughout their whole life she brings to life no more than 15 bear cubs.
The mating season for polar bears lasts from April to June. Each female bear during mating games gathers up to ten male bears around her, and the strongest of them receives a chance to impregnate her and continue his family line. A couple stays only for three days together, after which the male leaves on his own business and the female starts carrying her baby.
The pregnancy lasts for 230-250 days and at the last stage the bear falls into hibernation. Bear cubs are born without any fur, blind and deaf, weighing 500-750 grams and stay completely helpless until they are one month old.
It is necessary to note that the female bear’s milk is the fattest of all land mammals. That is why babies grow extremely fast. Even at one month old their eyes can open, at two months old they get their first teeth and their weight reaches 10 kilograms. At this time, they start moving around by themselves and their mother bear slowly starts getting them used to light and the cold of the world outside of their comfortable lair.
When bear cubs reach four months old, the family finally says goodbye to their lair and the cubs start their nomadic lifestyle. They accompany their mother for a year and a half on all of her travels and then they separate and start living completely independently. It is necessary to say that a female bear selflessly protects her children. She may even start a fight with a male bear that is brave enough to attack her bear cub (and for babies, adult males represent a very realistic threat).
A one-year old bear cub weighs about 80 kilograms and it is quite able to independently catch a small seal, and at two years of age, they reach the size of their mother and are completely ready for independent life.
Text: Mikhail Savostin. Translation: Elizabet Hesket «Alldivs». Photo: Uryadnikov Sergey, Vladimir Melnik, André Gilden, Eric Isselée, Tony Campbell.
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