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Range and Habitat: The brown bear has the widest range of any other species of bear in the world. Brown bears once roamed across much of the Northern hemisphere from North America across Europe and Asia. The North American population in Alaska and Western Canada remain fairly stable. They are found in small numbers from Western Europe to Eastern Siberia. Brown bears are very adaptable to a range from mountains to coast to forests. In North America they prefer tundra, alpine meadows and coastlines. The bears need a very large range - female bears have a range from 50 to 300 square miles and 20 to 500 square miles for males.
Habits and Adaptations: Brown bears are most active at dawn and dusk. All bears have beds where they can rest day or night. They often will have several spots scattered throughout their feeding territory. Brown bears also dig shallow pits in soil or snow and sometimes line them with branches. Bear trails are paths that are cut deeply into the grass since brown bears are creatures of habit and they use the same trails between feeding grounds every year.
An adult brown bear is the top of the food chain and has little to fear from other animals. Brown bear cubs that stray from their mother may be eaten by wolves, pumas or other bears. Amur tigers have been known to attack young bears.
Brown bears must eat enough food to store large amounts of fat needed to take them through their winter sleep. The bears begin to look for a place for its winter sleep early in the fall. They like a high mountain slope where there will be very deep snow. The deeper the snow the better the insulation. The bears will use their huge powerful paws to move rocks and stumps. Brown bears are not true hibernators because there is not a great change in body temperature, heart rate or metabolism and they do wake up if they sense a threat. They live on stored fat and they do not eat, drink or eliminate waste during their winter sleep called dormancy. They can be in the den for 5-7 months.
Bears are generally solitary except for mating season and a mother bear with her cubs. However, brown bears will come together where food is abundant, such as garbage dumps and spawning salmon sites.
Large adult males are most dominant and a mother with cubs is the most aggressive. Bears communicate with smells and sounds. The brown bear’s sense of smell is better than its sense of hearing and sight. They scratch and rub on trees to communicate territorial boundaries and reproductive status.
Diet: Brown bears are opportunistic omnivores. They eat whatever they find in season. They eat a wide variety of plants, salmon, small animals and carrion, insects and fungi. Most of the brown bear’s diet is made up of vegetation. The bears eat about 25 to 35 lbs of food each day. Kamchatka bears eat as much as 90 pounds of food a day.
Breeding and Maturation: Breeding occurs in May or June with the courtship lasting 2 to 15 days. The female bear will mate with multiple males every 3 years. Male bears will mate every year if a female is available. Female bears give off a scent when in estrus. A male may have to approach her several times as she snarls and strikes at him. Mating involves head bobbing, mock fighting and wrestling. The bears have delayed implantation (about 5 months after mating followed by 6-8 week gestation).
Both the males and females mature at 4-6 years, but they continue to grow until 10-11 years. Males often don’t breed until 8-10 years when they can compete with larger, stronger males.
The female gives birth in the den during the dormancy period. Between January and March the female gives birth to 1-4 cubs, with 2 being the average litter size. The cubs weigh less than a pound at birth. They are born blind, deaf and naked (altricial). Bears give birth to the smallest of all mammal young in proportion to the size of their parents. The cubs stay with mother 2-3 years and are weaned at 18-30 months. At 5 months they eat a variety of food. There is a 50 % mortality rate for cubs.
Males don’t help raise the young. A hungry male will prey on young so mothers and cubs are the last to emerge from their dens in the spring. Longevity is 25-30 years in the wild and up to 40 or even 50 years in captivity.
Conservation: The brown bears in Bhutan, Mongolia and China are listed as endangered. Brown bears are considered threatened under the United States Endangered Species Act in the lower 48 states. The brown bears in Alaska are not protected. They are important in the ecotourism industry. Conservation status depends on the population. Some are clearly endangered and others are not. The number of brown bears have dropped dramatically since the 1900's. They now live in 2% of their former territories. They are poached for their gall bladders and paws for traditional Asian medicine. The largest bears are hunted for trophies. The bears must compete with people for one of their main sources of food: salmon. Salmon is poached for their roe (eggs) and harvested for their meat. As people take more and more salmon there is less for the brown bears
Miscellaneous: The term “Grizzly Bear” has two meanings. To many Americans, a Grizzly is a large brown bear. This is the meaning we use in the title of this exhibit. The second meaning relates to the subspecies of brown bears identified in science as horribilis. This subspecies is actually a medium-sized brown bear from the northern plains (e.g. Montana and Canada). The subspecies exists and there is scientific agreement on the latin name. The popular name grizzly has no particular scientific meaning, though it is commonly used for this subspecies.
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