A polar or polar bear is the only one that is classified in most countries (USA, Norway, Greenland and Russia) as a marine mammal. The exception is Canada, which currently ranks the polar bear as a land mammal. Polar bears are at the top of the food chain in the Arctic, where they feed mainly on seals.
Who are polar bears?
According to the latest data from numerous studies, the brown bear is an ancient ancestor of polar bears. Their origin dates back to about 350 thousand-6 million years ago. Unlike their brown relatives, who live on land, polar bears are perfectly adapted for survival in the Arctic seas of the Far North. There are different populations of polar bears. In total, there are 19 species of various subpopulations of polar bears. According to more recent studies, four main groups are distinguished. This classification takes as a basis the features of the place where polar bears live: diverging ice, convergent ice, seasonal ice and archipelagos.
The polar bear is the closest relative to the brown bear. Adult males usually weigh between 350 and 600 kilograms. Adult females are smaller - usually their weight is from 150 to 295 kilograms. Polar bears are considered centenarians. In the wild, they live on average from 15 to 18 years, although biologists have recorded several 30-year-olds. In captivity, some long-lived bears reach 40 years of age. A striking example of this is the captive-raised Debbie bear from Canada, who lived to be 42 years old.
Where do polar bears live?
The habitat of the polar bear is its natural environment, where it can hunt for food and breed, constructing snow dens for hibernation and protection of young. Polar bears are found throughout the Arctic. They most often live in areas where the ringed seal population is found. The habitat of the polar bear covers the entire circumpolar Arctic.
These large mammals have adapted to live in water and on land. Unlike other bears, the polar bear is an excellent swimmer, and sometimes they can be seen more than 160 km from the ground or ice. Currently, more than 40 percent of all polar bears live in northern Canada, on the ice along the shores of numerous islands.
Threat of extinction
Polar bears are considered a rather vulnerable species in terms of extinction. In Russia, animals are listed in the Red Book, which includes rare or endangered animals. In the USA, white bears as an endangered species are listed on the Endangered Species list. Canada believes that they require increased attention within the threatened national species. Animal protection measures are taken at the legislative level.
The cause for concern is the loss of habitat due to climate change. Scientists predict that due to intense melting of ice, two-thirds of the global number of polar bears may disappear as early as this century. The study also shows that it is still fixable if measures are soon taken to significantly reduce greenhouse gas emissions into the atmosphere. Places where polar bears live should not be polluted due to the commercial use of the Arctic.
Polar bears: habitat
Bears are adapted to the Arctic climate, where the air temperature in winter can drop to -45º C. These animals have two isolated layers of fur that help them retain body heat. In addition, in good times, they also have a thick layer of fat. Compact ears and a small tail also prevent heat loss. In fact, polar bears have more problems with overheating than from the cold, especially when they run. Excellent sense of smell helps them to hunt, and their claws can keep prey at 40-90 kg.
The place of the polar bear in the food chain
The habitat of these furry predators are the Arctic deserts. The polar bear is located at the top of the Arctic food chain. Thus, a natural balance is achieved in order to prevent overpopulation of the habitat. When an adult bear is in good shape, formed fat stores support the body between meals.
Bears prey on ringed seals, sea hares, and baleen whales. These white and fluffy mammals are excellent swimmers: they use their front legs as oars, while their hind legs serve as a helm. In addition, they have a wonderful scent: they can smell their prey, being at a distance of one kilometer.
Progeny
Depending on the state of the body, females usually reproduce two or three cubs every 4-6 years. In this regard, polar bears have one of the slowest reproductive cycles in nature, bringing offspring, as a rule, no more than five times during life. The habitat of a polar bear allows you to choose a suitable shelter for the birth of cubs. Teddy bears are born in November or December in snowy caves, called tribal dens.
At birth, babies resemble large white rats, which reach a length of 30-35 centimeters and weigh a little more than half a kilogram. Blind, toothless and covered with short soft fur, they are completely dependent on their mother, receiving heat and food from her. Cubs grow quite quickly thanks to the high-calorie milk of their mother, whose fat content is about 31%. Little bears stay with their mother until they are 2.5 years old.
Habitat features
The habitat of the polar bear can vary, as animals can make long-distance migrations by land and water along the continental coasts or islands. Some individuals spend most of the year on land. Most pregnant females spend their autumn and winter on the ground in their birth dens.
The average air temperature in the Arctic reaches -34 ° C in winter and 0 ° C in summer. The coldest zone in the winter is the north-eastern part of Siberia, where the temperature drops to -69 ° C. The warmest areas in the summer are considered the inland regions of Siberia, Alaska and Canada, where the temperature can reach + 32 ° C.
Polar bears, whose habitat falls on the northern circumpolar regions, are often depicted in illustrations in popular art and children's books along with penguins. However, they live at different poles. Polar bears do not live in Antarctica: penguins live there on an ice-covered continent surrounded by oceans, and the polar bear's habitat is the Arctic.
Such they are, these amazing animals - polar bears.