Typical weights

Males of breeding age: 125-500 lbs or more

Females of breeding age: 90-300 lbs or more

Records

Male: 880 lbs (399 kgs), Craven Co., NC, 1998 or or 902 lbs (410 kg) field-dressed, Quebec, 1976

Female: 520 lbs (236 kgs), St. Louis Co., MN, Aug 30, 1993

Captive bears may exceed these weights.

Weight depends upon age, sex, season, food, and genetics. Males approach full size at 12 years of age. Females approach their smaller full size at 6.

Weight loss: Males that weigh 500 pounds in fall can lose 100 pounds over winter and another 100 pounds during spring mating season. Mature females can lose about the same percentage over winter and spring if they give birth and nurse newborn cubs.

Weight gain: The period of weight gain in the Northwoods is short—mainly summer. In parts of North America that have acorns, hickory nuts, and other fall foods, weight gain can extend through fall.

Supplemental food: Unusually heavy black bears usually have access to supplemental food. Researchers weighed such a bear near Orr, Minnesota, in 1994. Duffy, age 12, weighed 584 pounds on July 31 and 876 pounds on September 5 (photos), gaining 8.1 pounds a day those 36 days. On September 9, he went off to make a den. On July 4, 1995, he weighed only 465 pounds after losing 411 pounds (47 percent) during hibernation and mating. He had a gentle demeanor. He trusted people where he was accustomed to seeing them, and he allowed researchers to walk with him, but he remained wary of unexpected people. He survived far past the average age of 2 at which male bears are shot in Minnesota. A hunter shot him at the age of 16 ¾ in the area where he was used to seeing people.

General: Black bears are 4 to 7 feet from nose to tail, 2 to 3 feet high at the shoulders, and have small eyes, rounded ears, a long snout, a short tail, and light gray skin. Their fur is shaggy or sleek, depending upon season.

Compared to grizzly bears: Black bears average smaller than grizzly bears, have a smaller shoulder hump, and a less concave facial profile. Their claws are smaller and more tightly curved for climbing trees. Their fur is less shaggy. Their ears are longer, smoother, and more tapered. They have a furred rear instep, unlike the grizzly.

Fur color: Black bears come in more colors than any other North American mammal. They are almost always black in eastern populations but are brown, cinnamon, black, or occasionally blond in western populations. Other color phases are white and bluish-gray as shown in the page on color phases.

Individual black bears can be recognized by:

• the muzzle color and pattern of black, brown, and blond fur
• the shape and shade of brown of their eyebrow patches, if present
• the shape and extent of white chest patches, if present. These range from a few white hairs to conspicuous patches.

Cub traits: Cubs' blue eyes turn brown within a year. Brown patches on the front and back of their ears usually disappear within a year.

Saggital crest: This protrusion is for attachment of chewing muscles. Animals with a large saggital crest have a powerful bite. The saggital crest is much bigger on male black bears than it is on females, giving males a more powerful bite when fighting over females. Males and females have similar diets.

Teeth: Black bears have 42 teeth adapted to an omnivorous diet of vegetation, nuts, berries, insects, and some meat.

• The incisors can be used for cutting meat but are usually used to clip grass, clover, and newly emerging plants on the forest floor.
• The canines can be used to grasp prey and to wound opponents but are usually used to tear open logs for ants and grubs.
• The premolars are the four teeth behind each canine tooth. Usually the 2nd and 3rd premolars on the bottom jaw are missing, leaving a space (diastema) like herbivores have. Moose use their diastema to strip leaves off branches as they draw the branches sideways through it. Black bears use it the same way when eating young leaves in spring.

The molars are the 2 back teeth on the top and the 3 back teeth on the bottom. They are broad and flat like they are in raccoons and people and are used for crushing nuts and acorns and for grinding up vegetation. Black bears eat little meat, so they don't need their molars to be sharp and scissor-like as they are in animals like wolves and cats that eat mostly meat.

Daily Activity Period: Most bears become active a half-hour before sunrise, take a nap or two during the day, and bed down for the night an hour or two after sunset. However, some bears are active at night to avoid people or bears.

Core Home Range Diameter: Typically: Yearlings: 1-2 miles. Adult females: 2-6 miles. Adult males: 8-15 miles. Excursions to 126 miles recorded.

Social Organization: Matriarchal territoriality. Females hold territories. Males have mating ranges that usually include over 7 female territories. Male mating ranges are indefensibly large, so there is overlap among males as well as overlap of the female territories within male mating ranges. Females allow their offspring to remain in their territories. Young males voluntarily disperse from their mothers’ territories when the males approach sexual maturity. This may be between 1 and 4 years of age, depending upon food and rate of development. Mothers attempt to expand their territories at the expense of non-kin neighbors.

Late summer activities: In northeastern Minnesota, 40% of the females and 67% of the males traveled 4 to 125 miles outside their usual areas before returning for hibernation.

Vision: Bears see in color and have sharp vision close-up. Their distance vision (over two hundred yards) has not been tested.

Hearing: Hearing is the black bear’s first line of defense against danger because they can hear in all directions (unlike smell) and they can hear farther than they can see in brushy forest. Their ears develop to full size more quickly than the rest of their body. Their hearing is over twice the sensitivity of human hearing and exceeds human frequency ranges.

Smelling: Their smelling ability is extremely good. The limits are untested. Their nasal mucosa area is about 100 times larger than in humans.

Intelligence: Large brain compared to body size. One of the more intelligent mammals. Navigation ability superior to humans. Excellent long-term memory. Can generalize to the simple concept level.

Vocalizations: Usually silent (except in movies in which sounds are dubbed in). A variety of grunts in amiable situations. Loud blowing noises when frightened. Clack teeth when frightened. They use a resonant, humanlike “voice” to express a range of emotions from pleasure to fear. Does not threaten by growling (except in movies). In story-telling, any sound a bear makes is called a growl. Click here to learn more about black bear vocalizations.

Swimming Ability: Good. Speed and distance limits are untested. Can swim at least a mile and a half in fresh water. One swam more than 9 miles in the Gulf of Mexico. Can swim to island campsites.

Running Speed: Lean bears can exceed 30 mph. Can run uphill, downhill, or on level ground. Fat bears in winter coats overheat and tire quickly.

Preferred Foods: Nuts, acorns, fruit, insects, succulent greens. Meat and less succulent greens are eaten when preferred foods are scarce. A scarcity of preferred foods can result in failed reproduction, stunted growth, failure to add optimal amounts of fat, and death of young bears, especially cubs.

Ideal Habitat: Black bears like large forests with a variety of fruits and nuts. Many kinds of berries and ants are especially productive in sunny openings. Lowlands and wetlands add succulent vegetation. Pools and streams help bears cool off. Mothers with cubs prefer large trees (over 20 inches in diameter) with furrowed bark (like white pines or hemlocks) for bedding sites and refuge.

Mating season: Late May through June in northeastern Minnesota but into August in eastern and southern states. Males are ready to mate throughout that period but each female is ready for only a few days.

Implantation: Eggs are fertilized at the time of mating but wait until November to implant in the wall of the uterus and begin development.

Birth dates: Usually mid to late January in most areas. January-February in southeastern states.

Litter size: Typically 2 in western North America and 3 in eastern North America. First litters are often 1 or 2 cubs. Record: 6 cubs in Pennsylvania.

Birth Weight: Usually less than a pound. Bear cubs are the smaller at birth, compared to mother weight, of any placental mammal.

Parental Care: Offspring stay with their mothers for 17 months (or rarely an extra year) and may stay in her territory for several more years.

Sex Ratio: 50:50 at birth.

Sex Ratio at Maturity: 1 male per 2-5 females. Young males are more likely to die from human-related causes than are young females because subadult males leave their mothers’ territories and often travel through residential areas.

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