There is an ongoing debate whether black bears truly hibernate in the winter. Their metabolism does not slow down as much as that of groundhogs and other “true hibernators”. Also, their body temperature may drop only 10-15 degrees and their heart rate doesn’t slow as drastically. Some bears have been know to rouse immediately from their winter slumber, startling hikers and researchers.
On the other hand, some black bears sleep through the entire winter without so much as changing their position. “True hibernators” do stir regularly to eat and deposit bodily waste.
During the late summer and autumn black bears go through a gluttonous period to prepare for their long winter sleep. A bear who would normally eat about 4,000 calories a day will consume as much as 20,000 calories and forage for as much as 20 hours daily.
Today most black bears nest on the ground or in caves. They generally make a nest of leaves and other forest litter. Some researchers believe this may be the result of timbering practices across the black bear’s range. In the old-growth forests of the Great Smoky Mountains National Park, black bears have shown a definite preference for nesting in trees. Bears have been found as high as 80 feet above ground in the Park.