A polar bear is a member of a unique bear species which has specially adapted itself to the Arctic environment. Polar bears can be found throughout the Arctic, in what scientists believe to be at least 19 different subpopulations. These large animals are considered quite beautiful and majestic by many people, and in some regions they have been used as symbols of the Arctic and Arctic culture. The polar bear is also an animal of special concern and interest to scientists, because polar bear populations are very vulnerable to things like climate change and human encroachment.
The formal name for the polar bear is Ursus maritimus. These bears are among the largest predators in the world, reaching weights of up to 1,300 pounds (600 kilograms), with streamlined bodies which are designed for extremely efficient hunting. Polar bears have adapted a number of features for the Arctic environment, including a thick layer of insulating blubber, hollow translucent hairs which help trap warm air next to the skin, and small ears and tails to minimize heat loss. They also have large feet, which help distribute their weight evenly across thin ice and snow.
The distinguishing feature of the polar bear to many people is the classic white coat which the animals have right after molting. In fact, the hair of a polar bear is not white, as discussed above; the hairs simply refract light in a way which makes them appear white. Polar bears can also turn yellow as their hairs age and become stained, and in captivity, polar bears can turn green, as algae colonizes their hollow hairs.
Most polar bears eat a diet of seal, walrus, birds, and sometimes seaweed and fish as well. The animals have adapted muscular legs for killing their prey at one blow, along with a hefty set of teeth for efficient consumption. Polar bears live for around 20 years in the wild, and biologists estimate that there are around 20,000 to 25,000 polar bears roaming the Arctic today.
These animals are considered threatened, and in some regions they are listed as endangered species. Polar bears have experienced habitat pressure as a result of shrinking icecaps, combined with expanding human populations in the Arctic. Some polar bears are starving because they are unable to find food, while others are shot because they are a nuisance for human communities. These unfortunate circumstances have led some biologists to express alarm over the fate of the polar bear, suggesting that the animals could vanish in the wild by the middle of the 21st century.
