Polar bear

(Ursus maritimus)

Habitat and Distribution: Found in coastal regions, islands, and seas in the Arctic above 70° latitude. The southernmost populations depend on sea ice that forms yearly along the shoreline during winter months—this is their hunting grounds. While most of the northern population is able to hunt year round on the permanent ice, they are rarely seen close to the North Pole.

Size: 8-11 feet tall; 6.5-10 feet long; 330-1,500 pounds. Males are larger than females.

Wild Diet: Polar bears rely on blubber, which contributes to the 4-inch layer of fat under the skin that allows them to survive Arctic temperatures. They primarily get blubber from ringed and bearded seals, but sometimes harp and hooded seals. They will also sometimes eat walruses, belugas, narwhals, and carcasses of bowhead whales, typically when these animals have washed ashore.

In summer, when ice floes retreat, some polar bears are able to follow the ice—sometimes traveling hundreds of miles—to stay with their food source. Those who are stranded on land must resort to eating foxes, hares, birds, fish, grass, berries, willow, and seaweed, but they no longer have a good source of blubber. With increasing global temperatures, the ice-free summer season is beginning earlier and lasting longer.

Predators: Humans, other polar bears

Reproduction: Polar bears mate between April and June. When pregnant females are almost ready to give birth, in late October or early November, they dig maternity dens. Cubs are born between late November and early January. Twins are most common, although scientists have reported an increase in single births over the last 30 years. Newborn cubs are about 10-12 inches long and 2 pounds. Mothers bring their cubs out of the den between late February and April and stay with them for 2-3 years.

Behavior: Polar bears are usually solitary, though cubs will group with their mother and groups may gather near an abundant food source. When polar bears encounter each other, the smaller bear usually runs away, but a female with cubs will charge a much larger male to protect her babies and their food. Pregnant females den for the winter but do not hibernate. Males and females of all ages may den temporarily to avoid harsh weather.

Conservation

IUCN Status: Vulnerable

The major threat to polar bears is the melting of Arctic sea ice due to global climate change. Without sea ice, polar bears have no way to reach seals, their primary food source. This results in fewer, smaller offspring with higher mortality rates; it also keeps polar bears on land year-round where they are more likely to be hunted for fur, meat, or medicines. Proposed oil development in the Arctic also poses a variety of threats including oil spills and increased human-bear interaction. There are currently about 20,000 wild polar bears remaining, but at current rates of global warming, it is predicted that in 100 years they will be found only among the Islands in Greenland and the Canadian High Arctic.

However, it is not too late for each of us to join the effort to reduce global climate change. Learn how you can take action to protect polar bears and other wildlife.

 

Did you know?

  • Polar bears can eat up to 100 pounds of blubber in one sitting.
  • Their skin is actually black and their fur is clear and hollow.
  • They can travel thousands of miles every year to follow the seasonal movement of sea ice.
  • Kids can help to protect polar bear habitat. Find out how!