Friday, October 31, 2008
Scientists believe 1,500 black bears may live in Great Smoky Mountains National Park.
Great Smoky Mountains National Park is one of the few places remaining in the eastern United States where black bears can live in wild, natural surroundings. For many, this famous Smokies’ resident is a symbol of wilderness.
Bears inhabit all elevations of the park. Though populations are variable, counts conducted in 2006 indicated approximately 1,500 bears live in the park. This equals a population density of approximately two bears per square mile. At one time, the black bear’s range included most of North America except the extreme west coast. Because of the loss of habitat, the black bear is now confined to wooded areas or dense brushland.
All black bears in the park are black in color, but in other parts of the country they may be brown or cinnamon. They may be six feet in length and up to three feet high at the shoulder. During the summer months, a typical male bear weighs approximately 250 pounds while females are generally smaller and weigh less slightly over 100 pounds. However, bears may double their weight by the fall. Bears over 600 pounds have been documented in the park. Wild bears can live 12-15 years or more. "Panhandler" bears, who have had access to human foods and garbage, have a life expectancy of only half that time.
Bears, like humans, are omnivores. Plant materials such as berries and nuts make up approximately 85% of their diet. Insects and animal carrion provide valuable sources of protein for bears.
Bears have color vision and a keen sense of smell. In addition, they are good tree climbers, can swim very well, and can run 30 miles per hour.
Bears are most active during early morning and late evening hours in spring and summer. Mating usually takes place in July. Both female and male bears may have more than one mate during the summer.
Bears choose a denning site with the coming of cold weather. Dens are usually hollow stumps, tree cavities, or wherever there is shelter. Bears in the Smokies are unusual in that they often den high above the ground in standing hollow trees. Bears do not truly hibernate, but enter long periods of sleep. They may leave the den for short periods if disturbed or during brief warming trends.
One to four cubs are born during the mother’s winter sleep, usually in January. Bears weigh eight ounces at birth. Females with newly born cubs usually emerge from their winter dens in late March or early April. Commonly born in pairs, the cubs will remain with the mother for about eighteen months or until she mates again.
Habitual panhandler bears must be aversive conditioned or destroyed. If the bears are managed soon after they start to lose their wild behavior, they have a better chance of returning to natural food foraging behavior. Until 1991, the park’s management policy centered on live trapping problem bears and relocating them away from developed areas. Frequently, they returned and had to be trapped repeatedly or removed from the park entirely.
Now wildlife managers use proactive aversive conditioning that involves capturing, working-up, and releasing bears back into the same area. The work-up involves tranquilizing the animal and performing a safe medical examination on the bear. While the procedure is harmless to the bear, it is unpleasant and re-instills a fear of humans. This approach allows bears to remain in their home range, but they shy away from the developed areas.
In addition, bear-proof garbage cans have been replaced with larger bear-proof dumpsters. Volunteers and park staff diligently patrol the busiest picnic areas in the evenings to watch for potential problem bears and to clean up any trash that has been left out. Public education and law enforcement efforts have also been stepped up. So far the results are encouraging and the number of problem bears has been reduced.
Other Threats to Bears
Non-Native Species: The European wild hog is one of the most direct threats to the black bear. These pervasive intruders feed on the acorns and other mast that is a mainstay in the bear’s diet. Another exotic species, the gypsy moth, is headed southward. This insect defoliates oak trees, weakening them. Not only could the bear’s food source of acorns be affected, but some of the prime denning spots in old growth trees may be lost.
Poaching: Unfortunately, the lure of high profits on international markets encourages the poaching of black bears. Several cultures believe that bear gall bladders, paws, and claws have medicinal powers or consider them gourmet delicacies.
Urban Encroachment: Community and private developments near park boundaries are causing a loss in habitat for the bears. Poaching activities can be somewhat curtailed, and bear populations can eventually rebound from the losses. But once the critical habitats are destroyed, major declines in bear populations are inevitable. In addition, bears that venture outside park boundaries into neighboring communities may encounter human food and become unpredictable and dangerous "nuisance" bears.