Minnesota Profile: Black Bears
Forests in northern two-thirds of state, expanding south and west. Bears grow faster and reproduce better in food-rich upland forests, but live longer in lowland black spruce and cedar swamps, where they are less heavily hunted. In the 1800s black bears occupied southern Minnesota, while grizzly bears inhabited the Red River valley.
About 23,000 bears -- up 40 percent since 1991. Vital statistics: Adult females average 160 pounds; adult males, 300 pounds; a few have exceeded 800 pounds when fed by humans.
Spring diet of green vegetation: grasses, clover, dandelions, wild calla, aspen leaves and catkins. Early summer: Ants and ant pupae make up 60 percent of the diet. Mid-summer: sarsaparilla, wild berries. Early fall: berries of dogwood and mountain ash, hazelnuts, acorns. Bears also eat corn and oats. Many people feed birds during the summer, and bears don't know that little containers of sunflower seeds are birdfeeders and not bear feeders.
Up to 100 miles on fall foraging forays. Return to summer range to den. Their remarkable ability to return home makes translocation an unproductive way to deal with nuisance bears.
A model for extended space travel, hibernating Minnesota black bears can lie in one place for six months without suffering bone or muscle loss, though they lose 15 to 25 percent of their body weight. They go into hibernation between September and November and generally come out of the den in April. Sows give birth in late January or early February. Hibernating bears can be easily aroused because their body temperature remains high, but they can go all winter without eating, drinking, urinating, or defecating.
Average litter size: 2.6 cubs. Sows alone raise cubs. Eighteen percent of cubs die their first year. Lifespan averages three to five years. The top three causes of death of adult bears: hunting, nuisance killing, and motor vehicle collisions. Without these, bears can live 30 years.
By Dave Garshelis, DNR Bear Biologist