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polar bear group 512x219The Arctic Refuge, along with Alaska Maritime Refuge, are the only Refuges within the National Wildlife Refuge System that are home to all three species of North American bear (black, brown, and polar).

Topics on this page:
Polar Bears
Brown (Grizzly) Bears
Black Bears

Polar Bears

It's a magnificent, powerful, and fearless animal; the world's largest land carnivore. The polar bear is a unique part of our natural heritage - directly connected to the Arctic Refuge. How? Every year, several of these impressive animals come to the Refuge to den and give birth. Up to 50 others congregate along the coast of the Refuge in October and November.

These bears are part of the Southern Beaufort Sea population, estimated at 1,500 animals. They use an area extending more than 800 miles along the north coasts of Alaska and Canada. The bears spend most of their time on the drifting pack ice, feeding, resting, and denning. Each year, however, many of the pregnant females come to shore to dig maternity dens in snow drifts. Also, an increasing number of bears spend time on land while they wait for near-shore sea ice to form.

Pregnant females move onshore in late fall. When and where they go depends on weather, formation of sea ice, and snowdrift patterns. The pregnant bears dig their dens in November, then give birth to one or two tiny cubs in December or January. The mothers nurse and care for the young until March or early April, when they emerge from the dens. After several days getting used to the outside environment, including short trips to strengthen the cubs, the families leave the dens. They move back to the sea ice to hunt ringed seals and other prey. The cubs stay with their mothers, learning to hunt, for about the next two and a half years.

Along Alaska's coast, the highest density of polar bear land dens occurs within the Refuge. Many more dens have been found here than would be expected if bears denned uniformly along the coast. One reason may be that the Refuge coastal plain and northern foothills have more uneven terrain than areas to the west, allowing snow drifts to form more readily. Within the Refuge, bears have denned in the Canning River Delta, Camden Bay area, and Pokok Lagoon bluffs.

The Arctic Refuge is the only national conservation area where polar bears regularly den and the most consistently used polar bear land denning area in Alaska. These are just two of many reasons the Refuge is such an incredible natural area.


More information about conservation efforts, safety in polar bear habitat, and viewing the bears, is available in Plan your visit: Things to do before you come and In the Community.

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Brown Bears

Brown bears are the undisputed monarchs of the open tundra and mountains of Alaska. On the Arctic Refuge, they live farther north than any others of their species. Also called grizzlies because of the "grizzled" blond tips of their fur, brown bears can be shades of cream, brown, or black.

Brown bears escape the Refuge's long winters by hibernating for up to eight months each year. During this long sleep, bears do not eat or drink. They do, however, give birth and nurse their cubs.

Outside the den, brown bears explore widely for foods that are often in short supply. While spring snows remain, bears eat carrion, ground squirrels, and roots. In early June, some bears, especially sows with young, prey on newborn caribou. This opportunity lasts only a few weeks, until the calves are too nimble to catch. During the summer, brown bears feed mainly on greens. Some search high into the mountains for new growth emerging from late-melting snows. Later, the bears consume large quantities of berries. When snows return, often by mid-September, the bears again dig for ground squirrels and roots.

Most Refuge brown bears den in the mountains south of the coastal plain. Because the Refuge is underlain by permanently frozen ground, bears select rock caves, or sandy soils that have thawed more than four feet deep. The soils can collapse easily unless the top four inches are frozen, so bears must wait, usually until mid-October, for a hard freeze before excavating their dens.

Brown bears on the Refuge are faced with a long winter hibernation and limited food resources. As a result, they have smaller bodies than many other brown bears in Alaska, low reproduction rates, and slowly maturing young. This northernmost population has remained remarkably stable, however. The only enemies these monarchs have are old age, other brown bears, and occasionally people.

Though population densities are lower than many areas of Alaska, brown bears are plentiful on the Refuge. Listening at night through paper-thin tent walls, walking through dense willows, or cresting a hilltop - the possibility of meeting a bear heightens our senses. Without these magnificent animals, the special wilderness quality of the Arctic Refuge would be greatly diminished.

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Black Bears

Black bears are the most common species of bear in the United States. Smaller and more adaptable than either polar bears or brown bears, black bears live in forests on the south side of the Brooks Range mountains within the Arctic Refuge. Although they are called "black" bears, these animals may also be light or dark brown in color.

Black bears are very opportunistic while searching for food. They will eat almost anything nutritious. In the spring they feed on new grasses and bulbous roots, switching to ground squirrels, carrion or newborn moose or caribou calves when the opportunities arise. Later in the summer, black bears feast on many different kinds of berries and insects found throughout the boreal forest.

These animals face a cold, long winter, so they need to build up large fat reserves to sustain them until spring. Bears are not true hibernators, but their heart rate and respiration slow down during the winter denning period. Within the Refuge, black bears may den in a rock cavity or they may dig into a hillside. While in their dens, the bears will not eat or drink, nor will they urinate or defecate.

Females give birth to their cubs within their dens in late January or early February. The cubs are hairless and helpless at birth, but quickly develop into moving balls of fur by springtime. Each litter usually has one to three cubs. To regain fat reserves for the upcoming winter, females may wean their cubs during the cubs' first summer. Depending on the availability of food, the cubs will den with their mothers for one or perhaps two more winters, after which the cubs are independent enough to leave their mother's side. Females will generally give birth to another litter the following winter.

Black bears tend to be solitary, secretive creatures, especially when trying to avoid brown bears, which may kill black bears found in their areas. In years when berries or other food is scarce, black bears increase their home ranges to be able to venture farther to find needed food items. When food resources are plentiful, they range over a smaller area and are more tolerant of other black bears.

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Page Photo Credits — All photos courtesy of USFWS unless otherwise noted.
Last Updated: Mar 22, 2016
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