Arctic Barren Ground Grizzly (Ursus arctos) are found throughout the Arctic. Adult boars will range from 400 lbs. to 800 lbs. with coats ranging from solid dark to blonde. Most old bears are darker in color and have a silver hump. I have observed these bears high on the mountain above sheep and in the wide open tundra of the coastal plain. The older boars seem to be most frequent in the side drainages away from human traffic. The arctic grizzly usually prefer being alone and will not hang around human neighbors. They are used to open territory. Bears will feed on anything that will fill their belly, but usually grasses, sedges, roots, berries and carrion. They have an excellent sense of smell. They are very much aware of their surroundings and have a good sense in hearing, sight and instinct. They can sense when something is wrong. They are very athletic.
I have seen where bears have killed and fed on many sheep at one location. I believe this is a combination of two situations. Bears will usually set up in a sharp draw where sheep frequent in a transversal zone and they ambush them at close range. They will use this spot over many years. I have found entire skeletons in these spots, layers deep, and from many different years. The other situation that is likely is a band of sheep will get caught in an avalanche or drifted snow and die of exposure and the bears find them in the spring.
Muskox often frequent the upper valleys in early fall while we’re there. Once observed they can be the high light of the trip to the arctic. In 2006, I watched 3 grizzly kill 4 Muskox, off of the Hulahula. The sow with two grown cubs would surround the Muskox and get them backed up to each other, while one bear would go in and make a kill. They continued this on the same group throughout the month of August. When we left in September 4 Muskox were dead.
Cubs will stay with mom for 2 1/2 years and then mom will bread with a boar in May and June. She will allow the boar to run her cubs off. The cubs will feed in the same spots their mom showed them. The Sows will have delayed implantation and the fertilized egg will attach itself to the uterus wall in late fall before she hibernates for winter. The sow’s health will determine the attachment of the egg and the number in the litter. If the Sow is in low health or high stress she will miscarry. The gestation period is 6-8 weeks.
The boars stay solo and are travelers. They have their favorite feeding grounds that they will frequent and areas where they can be a hermit and not socialize with other animals. In the spring they will actively pursue sows to mate.
Bear density is tough to study and areas will change and overlap. In the Arctic Density has been as low as 300 sq. miles per bear. Some years I might only see one grizzly and other seasons I will average seeing one a day. I believe this variation in density is due to feed sources and they will conjugate in berry patches and caribou calving grounds and where food source is high.
We will only target older mature boars. Harvesting these boars will have little effect on refuge resource and possibly help populations. These boars will consistently kill cubs. I have found three grizzlies between the Marsh Fork and Guilbeau Pass in the last 10 years that have been killed by larger bears. These bears all had punctures through the skull from teeth.
Brown and grizzly bears are classified as the same species even though there are notable differences between them. Kodiak bears (brown bears from the Kodiak Archipelago) are classified as a distinct subspecies (U. a. middendorffi) from those on the mainland (U. a. horribilis) because they have been isolated from other bears since the last ice age about 12,000 years ago. “Brown bears” typically live along the southern coast of the state where they have access to seasonally abundant spawning salmon. The coastal areas also provide a rich array of vegetation they can use as food as well as a milder climate. This allows them to grow larger and live in higher densities than their “grizzly” cousins in the northern and interior parts of the state
The Grizzly Bear resembles its close relatives the black bear (U. americanus) and the polar bear (U. maritimus). Grizzly Bears are usually larger than black bears, have a more prominent shoulder hump, less prominent ears, and longer, straighter claws. Polar bears are similar in size to coastal brown bears, but are more streamlined, lacking the hump. The varying shapes of these bears are adaptations to their particular life styles. Long claws are useful in digging roots or excavating small mammals, but are not efficient for climbing trees. The musculature and bone structure of the hump are adaptations for digging and for attaining bursts of speed necessary for capture of moose or caribou. Color is not a reliable key in differentiating these bears because black and brown bears have many color phases and polar bears may have stained fur. For example, black bear fur may be black, brown, reddish or even shades of grey and white, while brown bear colors range from dark brown through very light blond.
Grizzly 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.
Grizzly 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.
Bears on the Refuge are faced with long winter hibernation and limited food resources. As a result, they have smaller bodies than many other 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 bears, and occasionally people.
Grizzly 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.