Sow with cubs in Denali National Park and Preserve, Alaska (Tim Rains / NPS photo)

Accepted scientific name:  Ursus arctos alascensis (Clinton Hart Merriam, 1896); however many authorities recognise only two subspecies of brown bear in North America: the grizzly bear (U.a. horribilis) and the Kodiak bear (U.a. middendorffi).  This places these Alaskan bears in the subspecies U.a. Horribilis.

In 1918 Clinton Hart Merriam divided the North American brown bears into 86 subspecies based upon small physical differences, mainly relating to skull measurements.  Over time this list has been reduced but some experts believe that there is still sufficient evidence to warrant classifying five North American subspecies in addition to the widely accepted grizzly and Kodiak bear subspecies.  In this website we include those five subspecies; the Alaskan brown bear (U.a. alascensis) being one of them.  However, much of the following information, other than range, is similar or identical to that given on the pages for the Dall Island (U.a. dalli), Peninsular (U.a. gyas), Sitka (U.a. sitkensis) and Stickeen (U.a. stikeenensis) brown bears.

Description:  A large bear, most commonly dark brown in colour but can range from blonde through to black.  The often grizzled appearance is caused by the light coloured tips of the long guard hairs over the shoulders and back.  The bears have a distinctive hump on the shoulders and a slightly dished profile to the face.  The front claws are noticeably long.  There is considerable variation in size depending upon the food available.  Adult males typically weigh 135 to 390 kg, females 95 to 205 kg.  Adults are usually between 90 and 110 cm at the shoulder.  Bears from the interior are around two-thirds the size of the coastal and island bears of Alaska.

Range:  The brown bear of mainland Alaska, excluding the northwest panhandle, Kenai peninsula and the extreme southeast.  Most abundant along the southern coastal region where they have access to abundant spawning salmon.

Map showing the locations of the five Alaskan subspecies of Ursus arctos, of those proposed by Clinton Hart Merriam, which some still consider as bone fide subspecies. Four of these (in red name boxes) are now widely believed to be of the subspecies U.a. horribilis. The fifth (in the green name box) is the widely accepted subspecies U.a. middendorffi (the Kodiak bear). (Peter Fitzgerald/ subspecies data: Bear Conservation – Creative Commons Licence)

Habitat:  Open meadows, forests, sub-alpine mountain regions, tundra and coastal areas.  They will travel to areas where food is abundant according to seasonal variations.

Status:  Brown bears are listed as “of least concern” by the IUCN and listed in CITES Appendix II.  There are around 30,000 brown bears in total in Alaska (excluding the subspecies U.a.middendorffi).  Populations in Alaska appear healthy and productive. Densities vary depending on the quality of the environment

Life span:  Around 20 to 30 years in the wild.  The oldest recorded bears in Alaska were a 38 year old male and a 39 year old female.

Food:  The bears are omnivorous and eat plants, grasses, sedges, roots, tubers, seeds, berries, salmon, small mammals and carrion.  They will also predate upon moose and caribou, particularly newborn animals.

Behaviour:  The bears reach sexual maturity between the ages of four and seven years.  Mating occurs between May and July.  The bears go into winter dens usually in October or November and emerge in April, May or June.  Cubs are born in the den in January and February, litters usually being of two or three cubs but can be of one or four.  They will remain with the mother for two to three years during which time she will not become pregnant again.  Except for mating and for mothers with cubs, grizzly bears are solitary although they will congregate in groups where there are plentiful sources of food, such as spawning salmon, whale carcasses and sedge fields.

Threats:  Some populations are at risk from  Habitat loss, habitat fragmentation, and the resultant conflicts with humans.  Poaching including for body parts to be used in medicine seems to be an increasing threat for all bears although the relative isolation of some Alaskan populations may afford them some protection from this.  Hunting is generally well regulated and based upon reliable population estimates.  It seems likely that these bears are or will soon be affected by climate change either directly or indirectly as habitat and food sources change or disappear.


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Page updated 19 February 2021