Minnesota Outdoors: Black bears are creatures more often misunderstood
Black bears are beginning to wake up from the long winter’s nap. Some bears might’ve already emerged from their slumber and have ventured out from den sites to search for food. Although not considered a true hibernator such as chipmunks, thirteen-lined ground squirrels, and woodchucks, the American black bear, like all black bears and bears in general, snooze away the coldest months of each and every year.
March and early April are the months of awakening for Minnesota’s black bears. Having denned up several months ago—sometimes as early as September or as late as November—most black bears will have lost anywhere from fifteen to thirty percent of their body weight by the time April rolls around.
Black bears are fascinating mammals that are fairly abundant across their range. And though sometimes becoming problematic for homeowners, farmers, and apiarists, especially when natural foods are scarce, black bears are generally shy, elusive, and rarely observed.
While all bears do indeed sleep the winter away with notable decreases in their vital signs, periodic arousal does occur. Moreover, female black bears give birth to one to five cubs in January or February while “hibernating”. The cubs nurse throughout the winter months as their mother mostly sleeps.
Choices of dens and den sites are highly variable from bear to bear, year to year, and location to location. Some bears will crawl into brush piles or within the tangles of deadfalls and root-wads to spend the winter months. Other bears will rake together plush nests of grasses and other vegetation underneath the boughs of evergreens to sleep away the wintertime. And some bears go underground when such luxuries are available or utilize the confines of a snug roadside culvert to curl up inside of. This latter example of a den was used by a female black bear at Itasca State Park a few years ago. She and her yearling cubs used the culvert all winter long to sleep in.
During the months of rest, black bears do not eat, drink, urinate, or defecate—they survive solely on their fat reserves. Those reserves, which can amount to several inches thick inside their bodies, make up a substantial portion of a bear’s overall weight. And because bears don’t eat or drink during their winter snooze, very little nitrogenous waste accumulates.
That withstanding, when black bears at last appear in the spring they will have lost a significant amount of weight. Nursing females typically lose even more weight. It is for this reason that bears need to feed constantly on nutritional, high-protein and high-carbohydrate foods from early spring until late autumn. Their winter survival depends on it.
From April through the autumn months in woodlands and fields throughout much of Minnesota, black bears will be constantly eating and searching for more to eat. Bears need to gain as much weight as possible from now until when they den-up once again. Carrion is an important springtime food, as is the first new shoots of grass and other succulent forage.
However, as spring turns into summer and more diverse foods become available such as hazel nuts, acorns, berries, tubers, roots, herbs, grasses, and sedges, black bears begin putting on weight and accumulating fat. Animal matter, such as ants, grubs, beetles, small mammals, and white-tailed deer fawns are also eaten. Even so, a black bear’s diet generally consists of 75-80 percent plant material.
Upon a bear’s emergence come each springtime, the whole cycle of gaining weight begins in earnest. Mating occurs in June through July and female black bears give birth seven to eight months later. The cubs are born very small, around eight ounces to a pound, and are blind, hairless, and helpless. They will remain with their mother for usually two years while learning many important lessons of survival from their watchful and caring mother.
Black bears are extraordinary Minnesota mammals. Their remarkable senses and mostly bashful ways predispose them to live their lives out of sight, though problems do occur from time to time whenever their noses lead them to human produced food sources. Powerful and highly intelligent, black bears are creatures more often misunderstood and needlessly feared as we get out and enjoy the great outdoors.