Polar bears, iconic symbols of the Arctic, are found in Alaska. These marine mammals inhabit the northernmost regions of the state, navigating frozen landscapes and icy waters. Understanding their habitat, adaptations, and population status provides insight into the challenges they encounter in a changing environment.
Alaskan Polar Bear Habitats
Polar bears in Alaska primarily inhabit the state’s Arctic coast and the associated sea ice environments of the Bering, Chukchi, and Beaufort Seas. Their distribution is closely tied to the availability of sea ice, which serves as a crucial habitat for hunting, mating, and denning.
Within Alaskan waters, two main subpopulations exist: the Southern Beaufort Sea population and the Chukchi Sea population. The Southern Beaufort Sea bears are found along the northern coast of Alaska and extend into Canadian Arctic territories. The Chukchi Sea population occupies western Alaska, ranging as far west as Russia’s Wrangel Island and occasionally south to St. Lawrence Island. Terrestrial denning areas, where pregnant females create snow dens, are also present along the northern Alaska coast.
Life in the Arctic Environment
Polar bears possess specialized adaptations in the extreme cold of the Arctic. Their bodies are insulated by two layers of thick fur, with transparent, hollow hairs that trap warm air, and a substantial layer of blubber up to 4.5 inches thick. Their large paws function as snowshoes for walking on ice and as paddles for swimming. A strong sense of smell helps them locate prey from a distance.
Ringed seals are the primary food source for polar bears, though they also hunt bearded seals, walruses, and occasionally scavenge on beluga whale carcasses. Bears hunt by waiting at seal breathing holes in the ice or by stalking seals resting on ice floes. Pregnant females create snow dens, often on land or stable sea ice, where they give birth to one to three cubs in December or January. The cubs remain in the den until March or April. Seasonal movements of polar bears are influenced by the dynamics of sea ice, as they follow the ice edge for hunting opportunities.
Protection and Population Trends
Polar bears in Alaska receive protections under both the Marine Mammal Protection Act (MMPA) and the Endangered Species Act (ESA). They were listed as a threatened species under the ESA in 2008 due to sea ice habitat decline. These acts prohibit disturbance or harm of polar bears, with exceptions for subsistence hunting by Alaska Natives.
The two Alaskan subpopulations exhibit different population trends. The Southern Beaufort Sea population has faced challenges, experiencing a decline of approximately 40% between 2001 and 2010. While the population stabilized around 900 individuals by 2010, recent estimates suggest a further decrease to about 819 bears. In contrast, the Chukchi Sea population is estimated to be around 3,000 bears and is considered healthier.
The primary threat to Alaskan polar bears is climate change, leading to sea ice habitat loss and fragmentation. Reduced sea ice forces bears to spend more time on land, affecting their ability to hunt and increasing human-wildlife interactions. Oil and gas development activities in the Arctic also pose threats, including habitat disturbance and harassment of bears. Management efforts involve collaboration between the U.S. Fish and Wildlife Service, Alaska Native organizations, and international agreements to address these challenges and conserve polar bear populations.