Brown bears live in many parts of the northern hemisphere including North America, Europe, Siberia and Caucasus mountains. The two sub-species of brown bear, the grizzly (Ursus arctos horribilis), and the Kodiak (Ursus arctos middendorffi), live in North America.
The brown bear has the most widespread distribution in the Northern hemisphere and they live in tundras, alpine areas, boreal forests and open meadows. Current estimates of brown bear population are between 125,000-150,000 living in the wild.
Overview of the Brown Bear
The brown bear diet includes grasses, roots, insects, rodents, deer, salmon, mountain sheep and even Black bears. Current Taxonomy of the brown bear is:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Carnivora
- Family: Ursidae
- Genus: Ursus
- Species: U. arctos
While brown bears are generally solitary animals, they tend to gather around a large food supply for example, schools of salmon. Range is somewhat determined by food availability. An Alaskan bear’s range could be up to 1350sq kms, whereas a bear that lives where there is a large food supply would require a much smaller range of somewhere around 27sq kms.
Females reach sexual maturity at 5 years of age and mating occurs in early summer. Females give birth in spring and will have 1-4 cubs every 3-4 years. Cubs stay with the mother for up to 2 ½ years and infanticide by male bears is a problem. At birth cubs weigh 600-700 grams and can grow to 1.7m –3m (5.5 – 10ft) and weigh 100-700kg (220-1,540lb) as adults.
Brown bears have a hump between their shoulder blades and longer claws, (up to 10cm), than most other bear species, which the brown bear uses for digging. Like other bear species, the brown bear goes into a ‘winter sleep’. Contrary to popular belief, bears don’t actually hibernate. They enter a state of ‘winter sleep’ in which their body temperature drops just a few degrees. Due to their large mass, bears can store energy reserves and go into winter sleep without the need to reduce their body temperature drastically. They will still wake up occasionally to eat or urinate.
Interesting Brown Bear Facts
Young brown bears can climb trees, however, they lose this ability when they become sub-adults, unlike black bears who can climb trees all their lives. Studies have shown that brown and grizzly bears are more aggressive than the American black bears, and while there are more cases of black bear attack on humans, brown bear attacks are much more serious. Research into the North American hunting records shows many hunters being injured by brown bears and more claims that brown bears are more dangerous than black bears.
Brown bears are excellent runners reaching speeds of up to 56km, but, unlike black bears, they can’t climb trees into adulthood. Brown bears come in many shades of brown, from light to dark, and grizzlies are usually brown but their fur can be white-tipped (grizzled), which is how they got their name. Brown bears have been known to attack and even eat black bears. The smaller black bears tend to avoid encounters with brown bears and even leave an area when brown bears arrive.
Resources and further reading: Aspects of Evolution and Adaptation in American Black Bears and Brown and Grizzly Bears of North America and Brown Bear.
Roberta Goli - Roberta has a Bachelor of Science Degree (Zoology), has worked with animals for over 10 years and enjoys writing short stories and flash ...
