A black bear weighs from 150 to 500 pounds and eats just about anything.

About 23,000 black bears make Maine their home, the largest population in the eastern United States.

Maine’s black bears might hibernate from September to May without a restroom break.

Here’s a quick look at black bear ecology, thanks to former Maine bear biologist Craig McLaughlin, now in Utah:

Diet and range

Female bears remain within or close to the area in which they were born; males take a hike, roaming up to 50 miles.

Bears begin feeding in early spring on plant life in moist forest openings and wetlands. They forage for buds and new leaves of aspen, birch and maples, and on nuts from the previous fall’s crop.

Vegetation makes up most of the black bear diet, but they won’t pass up insects and colonial beetles, mammals, birds, reptiles, fish or amphibians. They’ll eat carrion or prey.

In summer, bears take advantage of ripening berries and abundant insects. Bears eat hazelnuts and apples in early September, and start to climb for beechnuts, often breaking the tops of beech trees as they eat. In southern and western Maine, black bears add acorns in the fall.

In northern Maine, bears are restricted to beechnuts, which fluctuate widely in abundance. Some years, beechnuts are scarce to nonexistent; other years, Maine’s woods are full of them.

When their natural food supply dwindles due to drought or nature’s cycles, bears head for town, eating garbage, bird food, bee hives and cultivated crops. Basically, they eat anything with an aroma.

Size and speed

On average, adult female black bears (sows) weigh between 150 to 200 pounds, while adult males (boars) weigh between 250 to 350 pounds. However, some boars can exceed 500 pounds.

Males reach 6 feet from nose to tail, and stand 40 inches at the shoulder. Females reach 5 feet in length but rarely stand more than 30 inches at the shoulder.

Although they appear clumsy, don’t be fooled. They are capable of short bursts of speed, and have been clocked at nearly 35 mph. Black bears are also strong swimmers, having been spotted swimming more than 1.5 miles to reach offshore islands.

Hibernation

In Maine, bears usually enter dens to hibernate from mid October to late November, and emerge in April. Food shortages, however, will drive bears into dens as early as September. Bears usually don’t eat, drink, urinate or defecate for the entire period

And despite being in a deep sleeping state, denned bears are easily aroused and will sometimes leave their dens if disturbed.

Reproduction

Reproduction is controlled by the nutritional condition of the female during fall. If sows are unable to find sufficient food, they rarely produce offspring.

Cub production in northern Maine is synchronized to regular, alternate-year shortages of late fall beechnuts. In Maine, females produce their first litter – usually two cubs – at 4 to 6 years of age. Subsequent litters average three cubs.

Black bears breed from July through August and give birth from late December through February. Newborns weigh about 12 ounces, are nearly hairless and depend on their mother’s warmth and milk to survive in the den.

Family groups den together the following winter, and remain intact for 14-18 months.

Bears can live up to 30 years in the wild, but due to human activities, food supply and cannibalism, few bears in a population ever reach 10 years of age.

tkarkos@sunjournal.com

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