Bears are not true hibernators, more accurately, they are dormant in winter. They maintain a near normal body temperature, unlike ground squirrels, which allow their body temperature to drop to near freezing temperatures. The advantage of a high body temperature is that bears can be aroused from their sleep if attacked in their den. However, maintaining a high body temperature costs many calories over a winter.

Reproduction is another motivating factor. Quite simply, bigger the bear, the better the chances of reproducing. In nature, passing on one’s genes in the only measure of success. For males, being bigger means access to females simply by being able to fight off other males. For females, stored fat is crucial to nursing a litter of 2 or 3 cubs for several months.

Bears mate in June but the embryo does not implant until fall, likely in response to adequate fat reserves in the female’s body. Cubs are born in February and are very small, less than 500 grams. They remain in the den for 3 months, and will weigh 4 to 8 kg by the time they leave the den in May.

Adult bears in the den do not eat, defecate, or urinate for 6 months. Through a fantastic metabolic feat they can emerge from the den after a winter’s snooze, having consumed 25% of their body weight. Bears are able to metabolize waste products and some how avoid the loss of bone density during their long sleep. They are able to accomplish this fast because they can eat so much during the summer. But this also why bears are attracted to prime sources of food and can be very aggressive towards possible competitors.

For these reasons, being able to identify bear foods is the first step in assessing bear habitat. Bears mostly eat plants, though they evolved from carnivores. Eating plants is less risky in terms of supply and potential for injury.

Bears eat a wide variety of plants. The following is a list of some of the more important ones in regard to availability and nutrition. These factors change with the seasons, elevation, and slope aspect.

• Roots; glacier lily, spring beauty, hedysarum
• Herbs; sedge, horsetail, cow parsnip, fireweed
• Berries; huckleberry, blueberry, mountain ash

Dominant male bears take the best feeding sites. Females and cubs use habitat of secondary quality to avoid confrontations with larger males who are aggressive toward anything that is competing for food. An exception to this is productive berry patches which can have concentrations of male bears in late summer and fall. The best huckleberry and blueberry patches occur about 25 years after a forest fire.
 

The presence of a bear can be assumed from the evidence of their activities. Interpreting the age of any of the signs of bear activity is key to assessing the significance of the sign.

Scats are obvious and can also be examined to determine what kind of food bears are eating. It is not possible to determine which species produced the stool. When bears eat green vegetation the stool is dark green. The longer it has been exposed to air, the blacker it will become. By using a stick to poke the stool apart, one can determine an approximate time of the bear’s having passed that spot. Stools darken faster during warm weather. Generally speaking, it takes a few hours for the outside of the stool to darken and a few days for it to darken right through. When trying to age a scat, consider the recent weather.
 

Tracks can assist in determining species. Black bears have more of an arch in the pattern of the toes and the claw marks are close to the toes. Grizzly claw marks are farther in front of the toes. A grizzly’s claw length diminishes with summer because of digging. The size of the track is not a reliable indicator of the species as there are small and large bears of both kinds. Tracks in snow will become larger as the snow melts.

The most frequent sign of bear activity is trampled vegetation in or between feeding areas. Look for these trampled vegetation trails in natural travel corridors and sites rich in succulent green vegetation.

In some areas, claw marks scar aspen trees. These become black with age and remain on the tree as a permanent scar. Black bears will feed on the seed heads of aspen during early spring. Look up when in this type of forest.

Bears communicate their presence to each other by leaving their scent on convenient trees on travel corridors which sometimes are also human trails. Look for prominent trees that protrude into the trail somewhat. Typically a bear will brush past it. Less frequently, it will stand a use it as a back-scratcher. This action can leave behind a few hairs caught in rough bark or in pitch. Silvertip fur reveals the presence of a grizzly. Note that hair roots can be light coloured too.

Bears will tear bark off subalpine fir trees and, to a lesser extent, spruce trees and rake their front teeth along the cambium layer for a sticky treat. Typically, the resulting bark damage is pointed at the top end. These scars do not heal but weather to grey wood.

Both species of bears will scratch around and turn over rocks and logs looking for insects. Only grizzly bears will dig for bulbs to such an extent that some sites appeared to have been tilled. Typically these are subalpine meadows rich in avalanche lilies. These showy yellow flowers are obvious in spring but take on an elongated form when the seed pod is ripe.

Check the dampness of the earth to gauge the freshness of the diggings. Again, the recent weather will have to be considered. Check to see the freshness of the vegetation under a clod of earth. If the flowers have yet to wilt, the digging is very fresh! Grizzlies also dig for ground squirrels, especially in the fall. These diggings can be a metre deep. These scars in a meadow can last many years indicating past bear use.

Bears move a lot. They are inquisitive by nature and capable of travelling large distances. When considering the activities of bears, think in terms of large areas with use varying with the seasons.