|Geographical Range||Arctic Circle: Greenland, Norway, Russia, Canada, Alaska|
|Habitat||Tundra, coastlines, floating ice blocks|
|Scientific Name||Ursus maritimus|
|Zoo Location||Polar Bear Point|
Built for the Arctic
Polar bears make their home on the islands, coastlines and floating ice blocks of the Arctic. They spend most of their time in the water in search of seals, walrus and fish. Their webbed paws and streamlined body form help make them expert swimmers.
Their white coat helps hide them in their snowy white world, an advantage when they want to sneak up on prey. The coat has an outer layer of guard hair over a thick layer of under hair, making it water repellent. Their feet are adapted for swimming in arctic waters and walking on snow and ice without freezing. The pads of their feet are covered with small, soft papillae which increases the friction between foot and ice, and between the pads there is thick fur to help keep their feet warm. Polar bears also have a two- to four-inch fat layer under the skin to add to buoyancy and insulation from the cold.
The polar bear is among the largest of the carnivorous quadrupeds. Females can weigh up to 650 pounds. Males can grow up to ten feet long and can weigh 900 to 1500 pounds.
As is the case with most bears, polar bears are not very social animals. Adults spend little time together, except during breeding season. The closest bond is between a mother and her young. Mother bears are very attentive to their cubs. They often stay in their birthing den for up to six months without taking in any food or water.
Threatened in the Wild
Polar bears are facing a major threat to their survival—loss of their sea ice habitat. Sea ice is essential to the bears for hunting seals on ice floes or near breath holes since polar bears are not fast enough swimmers to catch seals in open water. They stalk and ambush their prey on ice. Sea ice is also essential for mating and maternal denning. But over the last 20 years, scientists have noticed a marked reduction in Arctic sea ice. Recent modeling of future sea ice trends predicts dramatic reductions in sea ice coverage over the next 50 to 100 years.
In Canada’s Hudson Bay, for example, the sea-ice season has been shortened by several weeks, limiting the time that polar bears can prey on seals. This could be why scientists are finding thinner bears, lower female reproductive rates and higher death rates among young polar bears in that region. Many biologists blame global warming for the melting of sea ice. The world’s largest and oldest global environmental organization, the International Union for Conservation of Nature predicts that polar bear populations will drop more than 30 percent in the next four decades without a reversal of global warming trends.
Scientists are particularly concerned that polar bears may be less able to adapt to environmental changes than other bear species. Not only are they highly specialized for life in the Arctic marine environment, but they have low reproductive rates. This, combined with the current greater speed of global warming, makes it unlikely that the bears will be able to adapt to the current warming trend in the Arctic.
In May 2006, the International Union for Conservation of Nature reclassified the species as vulnerable by the International Union for Conservation of Nature (IUCN), an international organization involved in data gathering and analysis, research, field projects, advocacy, lobbying and education.
The polar bear has been listed as a threatened species under the Endangered Species Act since 2008 due to the imminent threat from climate change on their sea ice habitat.
The Zoo is Helping Polar Bears
Concerned about the rising threats to polar bears in the wild, the Zoo's WildCare Institute forged a partnership with Polar Bears International (PBI)— a non-profit organization dedicated to worldwide conservation of the polar bear and its habitat. Zoo staff have been actively involved with PBI to provide education programs to inform and empower people to make a difference by reducing carbon emissions that contribute to climate change. The Institute has also supported a PBI maternal den study conducted by scientists on the Alaska North Slope & Svalbard, Norway to document the denning behavior of polar bear mothers. Study results help wildlife managers and governing authorities develop plans to protect and preserve polar bears for future generations.