Black Bear

Nature Watch
September 17, 2008

By Susan Benson,
CNHM Director of Education

Do you like to eat? Probably not as much as a bear does. The black bear is a full-time, professional eater. Except during winter hibernation and a couple weeks in the summer during mating season, a bear spends all its waking hours looking for and eating food. Calorie-rich acorns from oak trees also are a favorite food for black bears. In fact, bears have been known to trek up to 50 miles to acorn-rich areas, and remember these spots from year to year. During the fall, bears prepare for upcoming hibernation by going into food frenzy -- they eat constantly and may gain up to a third of their body weight. In the fall, a hungry black bear might pack in more than 20,000 calories per day -- compare that to the average human's daily intake of 2,000 - 2,500 calories!

Black bears often are nocturnal, but may be active during the day, with activity peaks during early morning and late afternoon. In December they enter a winter den, which is frequently in a site with heavy ground cover with gathered bedding material. Black bears, unlike some mammals, are not true hibernators. They are easily aroused from their winter dormancy. Dormant black bears have a decreased heart rate and respiration, but their body temperature declines very little. They remain dormant for up to four months during the year, even when the weather is mild.
When walking outdoors, look for smooth-barked trees, such as aspen or birch, that have distinct slashes made by the bear's claws as it climbed a tree. Sometimes bears will chew on pine, spruce and fir trees, ripping off strips of bark near the base of the tree. They eat the sticky pitch inside the bark and will leave vertical tooth marks with their front teeth. Bears also mark trees to identify their territory and breeding status by rubbing themselves on specific trees and clawing the tree as high as they can reach.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 13470 County Highway M or on the web at http://www.cablemuseum.org/ to learn more about exhibits and programs.