The grizzly bear has the reputation of being the most ferocious and dangerous animal in North America. Grizzlies vary widely in body shape, color and in the shape of their heads. The tundra grizzly is often creamy yellow on the back with brownish legs and underparts. In the Rocky Mountains, the “silver-tip” phase is dominant. Adults weigh from 136 to 526 kg and are prodigiously strong.   

Although grizzlies try to avoid contact with humans,when encountered they are unpredictable and should be given plenty of room. They move with a slow shambling walk, the low-slung head swinging from side to side. They can move very quickly, however, and even horses find it difficult to evade a rushing grizzly. 

The Grizzily once inhabited almost all of western North America but, with the arrival of the Europeans in the 1500's their numbers were reduced until now they are restricted chiefly to the Canadian Rockies and Alaska with a small, healthy and growing population in the Yellowstone Region

Grizzilys occupy a variety of habitats, from the desert's edge to the high mountain forests, tundra, and alpine meadows. Grizzilys were common on the Great Plains prior to the arrival of European settlers.

Grizzily bears mature sexually between 4-6 years of age, but continue growing until 10-11 years old. Bears have been known to live and reproduce in the Greater Yellowstone area at 25 years of age and have a potential lifespan of 50 years.The number of offspring avg is 2 cubs. They stay with the mama sow for 2+ years.

Young grizzilys are born blind and furless, weighing only 340 to 680 grams. By 3 months old cubs weigh about32 pounds, by 6 months weight averages 60 pounds.

Brown bears in the wild can live for 20 to 30 years, although most brown bears die in their first few years of life. In captivity, brown bears have been known to live up to 50 years.

Three two year old grizzly bear cubs scratch on pole in Grand Teton National Park

The Grizzily may be active at any time of the day, but generally foragefor food in the morning and evening and sleep durning the day. Seasonal movements of the grizzily have been observed, with bears sometimes traveling dozens of miles during the fall to reach areas of favorable food supplies, such as white pine nuts and abundant berry patches.

Home ranges overlap extensively and there is no evidence of territorial defense, although bears are generally solitary. Occasionally, bears may gather in large numbers at major food sources and form family foraging groups with more than one age class of young.

Grizzilies begin hibernation in October to December, and they come out of their den in March to May, with the exact period dependent on the location, weather, and condition of the individual. Most often, brown bears dig their own dens and make a bed out of dry vegetation. Burrows are usually located on a sheltered slope, either under a large stone or among the roots of a mature tree. Dens are sometimes used repeatedly year after year.

Grizzilies move with a slow, lumbering walk, although they are capable of moving very quickly and can reach 35 miles per hour on short bursts. Grizzily bears have an excellent sense of smell and are able to follow the scent of a rotting carcass for more than two miles.

Brown bears are omnivorous, eating almost anything nutritious. Their diet changes with seasonal availability of different food sources. They eat a wide variety of plant foods, including grasses, sedges, roots, moss, and bulbs. Fruits, nuts, berries, bulbs, and tubers are taken extensively during summer and early autumn. They consume insects, fungi, and roots at all times of the year and also dig mice, ground squirrels, marmots, and other fossorial animals out of their burrows. Moth larvae have been demonstrated to be especially important sources of protein and fat when brown bears are putting on fat in the fall.

In the Rockies grizzly bears are quite carnivorous, hunting moose, elk, mountain sheep, and mountain goats. Occasionally black bears are preyed upon.

Because of their size and aggressiveness towards threats, brown bears are not often preyed upon. Humans have persecuted them throughout recent history and some cubs may be attacked by other bears, mountain lions or wolves, although this is very rare.

Grizzily bears have been long considered the most dangerous animal in North America, although real danger of attack from this animal is often exagerated. In general, brown bears attempt to avoid human contact and will not attack unless startled at close quarters with young or engrossed in a search for food.

Two year old grizzly bear cubs run playfully in Grand Teton National Park

Economic Importance for Humans: Positive

Grizzly bears have been widely sought as big game trophies and are currently subject to regulated sport hunting throughout much of their range. Grizzly bears help the ecotourism industry, especially in areas such as Yellowstone National Park, Wyoming and parts of Alaska.

Ways that people benefit from these animals.

Grizzly bear numbers have dropped dramatically since the turn of the century, when settlers and livestock flooded the West, driving these bears out of much of their former range. Grizzlies now cling to a mere 2 per cent of their former rnge. Logging, mining, road construction, resorts, subdivisions, golf courses, etc. have all encroached on suitable bear habitat, resulting in a decrease in bear numbers. Grizzly numbers were estimated at 100,000 in the conterminous United States in the early 1900's, but there are now fewer than 1,000. Brown bears are still fairly common in the mountainous regions of western Canada and Alaska, perhaps numbering about 30,000 individuals.

Three two year old grizzly bear sow and three cubs lounge around in Grand Teton National Park