On a recent trip to the far reaches of northern Minnesota for Black Bears I had a chance to photograph bears in their end of summer feeding frenzy. They were so intent upon feeding the challenge was not finding them it was getting them to lift up their heads long enough for a good picture.
There are three species of bear in North American. The Polar Bear, Grizzly Bear and the Black Bear. The Black Bear (Ursus Americans) is the most common and is the widest spread bear in North America. It ranges across the northern states and Canada from coast to coast with their range reaching like fingers down the Appalachian Mountains as far south as Florida and down the Rocky Mountains down to Mexico. In addition there are pockets of bears found in many southern states. Over all the population of Black Bears is growing all across the nation.
Black Bears are found only in North America. They inhabit forested regions but can also be found in mountainous regions, open tundra and more and more in suburban areas. There is an estimated 750,000 Black Bears in the US.
Each spring Black Bears emerge from their winter dens and begin to feed. They have lost so much weight over winter that it is very important for the bears to find enough food to regain their strength and energy in preparation for mating. Mating season starts in late May and extends into early July.
Summer is a good time of year for bears. Mating is over and living is good. Foraging for food and milling around their home range takes up much of their time. Insects are plentiful and their favorite food, green grasses and sedges are everywhere. Plants make up 80 percent of their diet.
Starting in late August, a Black Bear’s hormones kick into high gear which in turn starts the bears on a feeding frenzy. In order for a bear to survive 5 to 6 months of winter dormancy it needs to have a sufficient layer of fat from which the body draws its energy. Without enough fat stored the bear may not make it to the following spring. In addition the amount of fat and the quality of the fat will determine if and how many cubs a mother bear will have during the coming winter.
Although bears mate in June the prospective mother will not actually become pregnant until November. This is called delayed implantation and is fairly common in large mammals such as bears. So if a mother bear is healthy and has an adequate fat layer going into winter dormancy she will give birth to several (usually 2) cubs in January or early February. If she is not carrying enough fat see will not have any cubs.
So in preparation of the coming winter all bears at this time of year are in a hyperactive eating mode which is called hyperphagia. This leads to bears feeding for up to 20 hours a day, taking in huge amounts of calories. Most of the food stuff is in the form of plants but they also eat as many insects, berries and nuts as they can find. Years with droughts which result in few berries and nuts are tough on the bears and forces them to find alternative food sources such as breaking into cabins, tearing down birdfeeders and raiding garbage cans. The bears are so single-minded on eating at this time of year they sleep only a couple hours each day. The rest of the time is devoted to foraging for food. Some bears may travel hundreds of miles in search of a rich food supply. Until next time…