Ursus americanus
Black bears are the smallest and most common bear native to North America. They range from northern Alaska across Canada to the Atlantic Ocean, and south through most of the United States and into Mexico. They prefer remote, inaccessible areas. Because they are omnivores and consume large amounts of food, they require a mix of habitats such as forests, meadows, swamps, burned areas and avalanche chutes.
Black bears can be brown, cinnamon, blonde, creamy-white or bluish-gray. They do not go into a deep hibernation in winter, in fact, some do not den up at all.
Black bear behavior and facts
- Bear muzzles are usually paler than their fur.
- Black bears are diurnal (active during the day) but may be nocturnal (active at night) in areas with human food sources such as garbage dumps or farms, or in areas occupied by grizzly bears.
- As omnivores, their teeth are adapted to meat and plants. Flat, grinding molars at the back of their mouth pulverize plants and nuts. Huge canine teeth at the front rip chunks of meat off bones.
- They are territorial, with good navigation skills and senses of smell.
- Because of the large amount of food needed to sustain them, they are solitary, but may share overlapping home ranges. If food is plentiful, bears may come together..
- Males are most aggressive during breeding season.
- Other than humans, black bear have few predators. Grizzly bears, mountain lions and gray wolves sometimes prey on black bear cubs. Bears may kill each other for food, to reduce competition for scarce resources or, in rare cases, for mates.
Black bear diet
- The black bear's diet varies with the seasons and their location. They are opportunistic, meaning they will eat whatever is available.
- Spring diet: grasses, tree buds and tender shoots from trees like aspen, cottonwood and poplar, and forbs (broad-leafed herbaceous plants)
- Summer diet: soft mast (berries from shrubs such as huckleberries, strawberries) and insects
- Fall and winter: hard mast (acorns and other nuts; seeds like pine nuts)
- If food is scarce in the winter, black bears can slow their metabolism and spend months sleeping inside a den.
- In any season, they’ll eat leftovers from other carnivores (carrion). When other food sources are scarce, they’ll hunt mammals including squirrels, feral pigs, elk or domestic animals. They may also eat from garbage dumps, agricultural crops and orchards.
From birth to death
- Bears become more social during their breeding season in June and July.
- Litters: 1 to 5 cubs (usually 2) every other year if enough food is available to support a pregnancy.
- Gestation: approximately 220 days with a five-month implantation delay and an eight-week gestation
- Lifespan: approximately 10 years in the wild; in captivity bears can live into their 20s
Vital statistics
- Black bears can reach up to 6 feet tall.
- Weight:
Males: 150 to 600 pounds
Females: 90 to 200 pounds
Status
CITES Appendix II
Did you know?
Black bear tracks are sometimes found at Oxbow Regional Park and Cooper Mountain Nature Park. Find out how Metro is working with partners to protect natural areas and wildlife corridors for bear, cougar and other large mammals.
Wondering what other animals you might find in the Portland region? Want to learn to read animal tracks? Metro offers nature programs and wildlife checklists.
Black bears, the Oregon Zoo and you
The zoo’s black bears live in Black Bear Ridge. Their diet includes red meat, fish, fruit, veggies, fresh greens, and omnivore chow; a mix of foods, similar to dog chow, produced specifically to meet the dietary needs of omnivorous animals. Humans are the largest threat to bears through hunting, poaching and motor vehicle accidents.
