It has been reported that animals killed by black bears constitute less than one percent of the bears diet. Nesting birds, penned livestock, and fish are among the bear s diet, in addition to blueberries, corn, and honey. The bears use their sense of smell in order to locate desired food Black bears hibernate as a way of avoiding the scarcity of food brought by the long Maine winters. Bears select dens in which to sleep which include hollowed out trees and caves. Bears make insulative beds for their dens by gathering leaves, twigs, and grass.
Bears hibernate alone in their dens except for mothers who sleep with their cubs.
During hibernation, usually from December to April, the bears metabolic rates are cut in half and the sleeping heart rate drops to between 8 and 40 beats per minute from between 60 and 90 beats per minute. Black bears are not true hibernators as they sometimes leave the den for short periods of time. It has been reported that less than one percent of bears die during hibernation. In January, new cubs are born weighing less than one pound with a light covering of fir. By the age of 2 to 3 months, cubs are able to leave the den with their mother.