August 19, 2017

Bear Bio

BROWN BEAR (Ursus arctos) ARE FOUND THROUGHOUT MOST OF ALASKA which is home to 98 percent of the United States population of brown bears and more than 70 percent of the North American population.

Though many people consider brown bear and grizzly bears as different species, including many taxonomists, technically brown bears and grizzly bears are classified as the same species, Ursus arctos. Brown bears in a few areas of Alaska, due to the specific genetic and physical characteristics of those bears, are classified as a distinct subspecies.

To help distinguish between brown bears and grizzly bears, as do many of the trophy record keeping organizations in the United States, brown bears are commonly referred to as the members of this species, Ursus arctos, which are found in the coastal areas of Alaska where the protein rich salmon is their primary food source. The bears of this species that are found inland or in the interior regions of Alaska are referred to as grizzlies. Grizzlies (Ursus arctos horribilis), or inland bears of this species, are usually smaller than coastal bears, primarily because they do not have as constant a supply or readily available supply of salmon as do the coastal bears. Brown/grizzly bears are omnivores, like humans, and eat a wide variety of foods. Their diet includes various berries, grasses, sedges, roots, rodents and fish as well as moose, caribou and deer. Bears are opportunists and will feed on what is available, including carcasses of animals.

Brown/grizzly bears are distinguishable from their relatives the black bear (Ursus americanus) because they are generally larger, have a prominent shoulder hump, smaller ears in proportion to their body and longer, straighter claws. The distinct shoulder hump and long claws of the brown/grizzly bear are physical adaptations to their feeding behavior. The longer claws are used for digging roots and excavating the borrows of small animals. The bone and muscle structure of the hump is an adaptation for power in digging and for attaining bursts of speed, up to 35 mph, necessary in capturing moose, caribou and deer for food. Color cannot necessarily distinguish brown/grizzly bears from black bears because both species can be found in various colors. Brown/grizzly bear colors range from light blond to very dark brown and black bears vary in color from shades of blue and white to brown and blond.

Brown/grizzly bears weight varies greatly depending upon the time of the year. Bears weigh the least in the spring and can have up to 25 to 35 percent weight increase over the course of the summer and fall and are the heaviest just prior to entering their dens in the late fall or early winter, at which point a mature bore (male) can weigh between 500 and 1,200 pounds. Females (sows) generally weigh about half to three-quarters as much as the boars. A large boar, when standing on it’s hind feet, can tower as high as 8 to 10 feet tall and when the hide or skin of a big boar is measured, it can square between 9 feet and 11 feet!

Obviously, being the same species, grizzlies experience the same seasonal weight fluctuations that brown bears do. In the late fall a mature grizzly boar can weigh between 400 and 800 pounds and can stand on its hind feet between 7 and 8 feet tall. When the hide or skin of a big grizzly is measured it can square between 7 and 9 feet! In many regions of Alaska the grizzlies tend to vary more in color than do brown bears and many grizzlies have beautiful blond bodies with dark brown legs.

Brown/grizzly bears have an absolutely incredible sense of smell and under certain conditions can detect odors well over a mile away. When hunting brown/grizzly bears the wind should always be a constant consideration and the successful hunter generally uses the wind to his/her advantage. Brown/grizzly bears have adequate hearing and eyesight, likely similar to that of humans but generally not nearly as poor as many people report or would like to believe. It is a misconception that bears stand on their hind feet to charge but instead it enables the bear to test the wind and see better.

Typically brown/grizzly bears are solitary animals and avoid the company of others, including humans, except for in the spring during the breeding season or when a sow is with her cubs. Exceptions to this rule are when primary food sources are heavily concentrates, such as spawning salmon in a river. In these situations many brown/grizzly bears can be seen in close proximity to each other.

Mating occurs from May through July with the peak of activity occurring in early June. A boar will mate with more than one sow during the breeding period and has no strong attachment to any particular female. The hairless cubs are born the following January or February in the winter den and weigh less than the pound. A sow may have between one and four cubs but two is most common. These cubs generally leave the sow two years later in May or June and following this separation the sow can breed again and produce a new litter of cubs the following year.

In the winter, when food is more scarce or unavailable, most brown/grizzly bears enter dens in the hills or mountains and hibernate through the winter months. While in the dens their body temperatures, heart rate and other metabolic rates are slowed and they go through a number of physiological changes. They develop a fecal “plug” which prevents them from passing waste which helps to keep their dens clean and they also recycle their urine to help prevent dehydration. Brown/grizzly bears do not truly hibernate in a technical sense. They spend varying amounts of time in their dens, usually between three and six months, depending partly upon the climate and a few never enter a winter den. Brown/grizzly bears generally reach an age of between 15 and 25 years old in the wild, though some have been known to live over 30 years.

Patience and glassing are two of the keys when hunting brown/grizzly bear. Various hunting conditions and terrain in different regions of Alaska require varying things from a hunter but time spent glassing and patience waiting for bears and specifically the right bear are two components that hold true just about everywhere. Hours of glassing with binoculars and spotting scopes is required to closely examine each bear a hunter sees to make sure it is not a sow with cubs and is a mature, big bear of trophy quality and that it has a good hide quality. A nice uniform hide is particularly prevalent in the spring when bears “rub” their hides to shed their warm winter coats preparing for the approaching warm days of summer. Patience is required in that hours or even days may go by on a hunt before a good, trophy quality bear is spotted and a hunter must have the patience to wait for the right opportunity to quickly and cleanly harvest the bear.

– Henry Tiffany with portions excerpted from the Alaska Department of Fish & Game Wildlife Notebook Series