Polar bears are large, white bears that like cold climates, fatty meals and long days of hunting. No matter how adorable polar bears look, these animals are not cuddly. In fact, polar bears are ferocious hunters, and they are the biggest carnivores among land animals.
The polar bear or the sea/ice bear are the world's largest land predators. They can be found in the Artic, the U.S. (Alaska), Canada, Russia, Denmark (Greenland), and Norway.
All recent indicators show that sea ice in the Arctic is melting at an alarming rate, a problem that needs to be addressed immediately if polar bears, and other species unique to the region, are to survive.
Polar bears feed primarily on the fat of ice-dependent seals. The remains of these seals provide food for many other Arctic wildlife species, giving polar bears a vital role in their ecosystem.
Polar bears are marine mammals, and spend much of their time on Arctic sea ice. A boar (adult male) weighs around 350-700 kg, while a sow (adult female) is about half that size. The polar bear is classified as a vulnerable species, with eight of the nineteen polar bear subpopulations in decline.
The babies are much smaller than human babies when they're born. They are the size of a rat and weigh little more than a pound. A polar bear's fur is not white. Each hair is a clear hollow tube. Polar bears look white because each hollow hair reflects the light.
Modern methods of tracking polar bear populations have been implemented only since the mid-1980s, and are expensive to perform consistently over a large area. The most accurate counts require flying a helicopter in the Arctic climate to find polar bears, shooting a tranquilizer dart at the bear to sedate it, and then tagging the bear.
The polar bear is an excellent swimmer and often will swim for days. One bear swam continuously for 9 days in the frigid Bering Sea for 400 mi (687 km) to reach ice far from land. She then traveled another 1,100 mi (1,800 km). With its body fat providing buoyancy, the bear swims in a dog paddle fashion using its large forepaws for propulsion.
The polar bear's most common hunting method is called still-hunting: The bear uses its excellent sense of smell to locate a seal breathing hole, and crouches nearby in silence for a seal to appear. The bear may lay in wait for several hours. When the seal exhales, the bear smells its breath, reaches into the hole with a forepaw, and drags it out onto the ice. The polar bear kills the seal by biting its head to crush its skull.
According to the World Wildlife Fund, the polar bear is important as an indicator of Arctic ecosystem health. Polar bears are studied to gain understanding of what is happening throughout the Arctic, because at-risk polar bears are often a sign of something wrong with the Arctic marine ecosystem. The key danger posed by climate change is malnutrition or starvation due to habitat loss. Polar bears hunt seals from a platform of sea ice. Rising temperatures cause the sea ice to melt earlier in the year, driving the bears to shore before they have built sufficient fat reserves to survive the period of scarce food in the late summer and early fall.
Changes in sea ice affect the ability of pregnant females to build suitable maternity dens. As the distance increases between the pack ice and the coast, females must swim longer distances to reach favored denning areas on land.