Basic: Alaska


Arctic Polar Bear, Ursus maritimus

Climate change is impacting all parts of the world today, but no regions are being hit harder than the Arctic and Antarctica. The 2007 Intergovernmental Panel on Climate Change reported that Alaska has seen a 3° C increase in temperature since the 1970s. Some models suggest the northern polar ice cap will be completely melted during summer months within a few short decades. The endangered Arctic region serves as critical habitat for endemic species such as the polar bear that depend on sea ice for survival.

Sea ice is melting in the north, and with it will likely go polar bear populations. This majestic creature depends heavily on sea ice, which acts as a platform during the species' prime hunting season in the summer months and provides a buffer against raging Arctic storms.

Polar bears are poor terrestrial hunters due to the high level of energy expended when walking; as a result, they depend greatly on aquatic marine life for survival. Polar bears have the capability to swim for extended periods of time; however, if they do not have a reasonable rest on ice packs or land, polar bears can easily die of exhaustion; likewise, as sea ice melts away, the bears must swim increasingly long distances from one floe to another, increasing the likelihood of exhaustion and drowning. The United States Geological Survey and others have found that numerous polar bear deaths result from starvation and exhaustion.

Polar Bear Habitat Distribution:

Polar bears breed during the summer months. Habitat degradation is contributing to declining cub survival rates and unstable denning conditions. As a survival mechanism, the female bear has the natural ability to abort if her body lacks nutritional content; this is ultimately leading to a decreasing population growth of a low reproducing species. Further, increasing temperatures are causing dens to collapse and other disruptions leading to unsuccessful survival rates of cubs. Half of maternal denning occurs on the ice pack.

The polar bear is an important part of the food chain of all species in the Arctic, including humans who rely on this food source as part of their subsistence lifestyle. The communities of Point Hope, Kivalina, Bering Strait/St Lawrence Island, Barrow, Shishmaref, Atqasuk, and Wainwright are known to hunt and consume polar bears.

In May 2008 the polar bear was listed as a threatened species under the Endangered Species Act. Subsistence harvest of the polar bear by Alaska Natives is still allowed as it is not deemed to be a threat to the species.

Fort Yukon Polar Bear
According to biologists of the U.S. Fish and Wildlife Service, the answer to "why the polar bear crossed the Brooks Range" is as clear as mud. Polar bears typically do not stray far from their saltwater ecosystem. However, in March of 2008 an individual was shot dead in Fort Yukon, Alaska, 250 miles from her Beaufort Sea habitat. That this happened in March, a foraging time for this northern marine mammal that preys on seals, makes the incident much more unusual.

Climate change may indeed be a piece of this puzzle. As the climate and ecosystems of the north change, so do the behaviors of living organisms. Is this a bear that is adapting to the changing environment? Polar bears, being bad terrestrial hunters, will need to find a new way to exist as the amount of sea ice decreases. Human beings may have to adapt along with the bears and realize this may become a frequent occurrence.

According to natural history, polar bears originally descended from brown bears. This species started moving north and so began to evolve a different shape of snout, hair color, as well as different hunting strategies in order to adapt to its new habitat. Perhaps one day this species will come again to where it began, completing its circular life history.

Marine Mammals Management, U.S. Fish and Wildlife Service polar bear website.
Accessed on March 31, 2008:

Mowry, Tim. March 28, 2008. Fairbanks Daily News Miner: Why did the polar bear cross the Brooks Range? Biologists are baffled.

For more information please contact:
Nikki Cooley, Co-Director
Karen Cozzetto, Co-Manager