Dare to Care for a Grizzly Bear
Answer Key

Log on to the “Windows into Wonderland” Web site at, http://www.windowsintowonderland.com/bears/index.htm. Explore Part 1 of the Electronic Field Trip, which focuses on Bear Ecology, and complete the information and questions below.

Student answers include: 

Name the foods grizzly bears eat.
Naturalist John Muir said “almost everything is food except granite;” grasses, sages, berries, and roots; human food and garbage; tree cambium, bird eggs, nuts, insects, elk calves, fish, elk and bison carcasses; cutthroat trout; roots, ants, rodents (such as pocket gophers), cutworm moths, and whitebark pine nuts. 

What is a grizzly bear’s “yearly schedule”? What do they do during the different months and seasons? 
From September through October, grizzlies go to high elevations to eat pine nuts found in the cones of the whitebark pine tree. By late fall, bears in Yellowstone are finding or digging their winter homes.

From November through March, grizzlies hibernate in their dens. 

Cubs are born during hibernation in January or February. 

From May to early July is mating season. 

What happens during grizzly hibernation?
During the months of hibernation bears do not eat or drink and do not expel body waste. They experience a drop in their metabolism, a reduction in body temperature, and a slowing of both their respiration and circulation. A bear’s heart rate will drop to 12 beats per minute, and its body temperature will lower to 94 degrees from a normal temperature of 100-101 degrees. These hibernation-related changes are less extreme in bears than in some other animals such as marmots or ground squirrels. Grizzlies can be easily aroused from hibernation and sometimes leave their dens during the winter. Adult males den alone, although there have been reports of newly independent sub-adult siblings sharing a den for the winter. Also, grizzly cubs are born during their mother’s hibernation period. The mother becomes semiconscious during the birth, but after delivery she continues to sleep for another two months.

What is the typical “home range” of a male and female grizzly?   
The male grizzly has a home range between 813 to 2,075 square miles, while female grizzlies cover 309 to 537 square miles.

How long do grizzly cubs stay with their mother? When do they leave her? 
Grizzly cubs may stay with their mother for as long as 3.5 years but usually seperate at 2.5. When the female grizzly is ready to mate again, she will drive her cubs away. This usually happens during the cubs’ second summer.

Name some differences between grizzly bears and black bears. 
Black bear cubs separate from their mothers earlier. 

An adult grizzly has a hump of muscle mass between its front shoulders, which is the highest part on its body when it is walking on all fours. Black bears do not have this hump, so if you see a bear on all fours and its rump is the highest point on its body, you are looking at a black bear. Also, the faces of adult grizzlies have a dished profile, while those of adult black bears have straight profiles. 

A black bear’s claws are shorter, stretching about 1.5 inches long, while the claws on the front foot of an adult grizzly are two to four inches long.

A black bear’s last upper molar is less than 1 1/8 inches long. The same tooth in a grizzly’s mouth is greater than 1 1/8 inches long.

Grizzlies can be twice as large as black bears of the same age and sex.

How long do grizzlies typically live? 
Grizzly bears usually live between 12 and 20 years, though some grizzlies survive into their late twenties.

What is the average weight of a male and female grizzly bear?
Males weigh between 300-700 pounds, and females weigh between 200-400 pounds.