Black bears are found in more than 30 states, and although they were originally found throughout most of Minnesota, they now live only in the northern woodlands. They are retiring, elusive animals that lead solitary lives except when the females are rearing their young or when concentrations of food bring them together. Surveys tell us that about 15,000 black bears went into hibernation in the winter of 2012-13 in Minnesota.

Peak time for Minnesota bears going into winter sleep is October. They pull in pine needles and other leaves for a bed that is usually dug under an overturned tree, but it might also be found within a sheltered cave, a dense thicket or a stand of small evergreens. Generally the bear is somewhat exposed and later becomes partly covered with snow, but its breath melts a hole in the snow where the bear den is found. A bear never gets up during the winter to eat, surviving off its fat storage until April, when it comes out of hibernation. It sleeps with its nose tucked down on the chest.

Although the bear's winter sleep is called hibernation, it is not in a complete deep sleep like that of, say, the 13-lined ground squirrel. It is rare, indeed, that a bear cannot easily be aroused from its winter slumbers despite the fact that it acts very drowsy.

Now is the time when black bear cubs are born. The young arrive in January or early February while their mothers are still sleeping in their dens. At birth, the young are usually two or three in number, each measuring 8 inches long and weighing 7 to 12 ounces, about a 500th of the weight of their mothers, who must nurse the cubs for three or four months with no food for herself.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.