Size - Ursus americanus, commonly known as black bears range from 89 to 102 centimeters (35 to 40 inches) tall when on all fours and have a length of 140 to 180 centimeters (4 1/2 to 6 feet). The weight of a black bear, which is highly variable, ranges from 57 to 272 kilograms (125 to 600 pounds) with males within a geographic area on average about a third larger than females. It has small eyes set close together, rounded ears, a long tan or grizzled snout, a large body, and a short tail. The largest American black bear to date was found in Riding Mountain National Park in Manitoba, Canada. It weighed in at 365 kilograms (805 pounds). Bears have forty-two teeth. Permanent teeth are normally in place by the time a bear is approximately two and a half years old. Black bears have premolars and molars for grinding their food.
Predators - The black bear's primary predator is man. It is the one bear species which seems to have the greatest capacity to live in close proximity to man. The only animal known to kill a black bear is a porcupine, when the bear gets the quills stuck in his tongue after trying to eat them and then dying from starvation. Bears can trot up to 30 mph in short bursts and are powerful swimmers. Will climb trees for food or protection. Rugged terrain and dense shrubs provide escape cover and den sites for black bears. Black bears also seek den sites under fallen trees, in hollow trees or caves, or in previously occupied dens. When possible, black bears will choose streams with dense bankside shrubbery as travel corridors to and from food sources. Primarily nocturnal, although it may be seen any time, day or night. Their curved claws are highly adapted to tree climbing and all black bears are agile tree climbers.
Lifespan - The life span of black bears in the wild can be twenty-five years or more. The oldest known black bear was 30 years old. (1985)
Color Phases - The fur color of the black bear is often, in fact, black but color phases can also include light brown, dark brown, cinnamon, beige, and even a blue-white color. There is evidence to suggest that in areas of relatively high rainfall, black bears predominate while in the drier inland areas of the continent, brown and blond bears are more common.
Diet - Eating virtually anything edible, it has been determined that more than 75% of their diet consists of vegetable matter including, berries, flowers, grasses and sedges, herbs, tubers and roots, and nuts of all kinds. For the remaining portion of their diet, animal matter such as decaying animal carcasses, fish, small marine animals, ants and other insects, honey, elk and moose calves and a variety of other small mammals (e.g., ground squirrels, marmots, etc.) are consumed. Black bears like to feed in the cool of the evening or in the early morning. During the heat of the day, they will often seek shade in the dense underbrush.
Senses - Excellent sense of smell. Good hearing and thought to have poor vision. Recent studies have shown that a bears eyesight is fairly good. A bears eyes are reflective and mirror the slightest light like a deer.
Breeding - Black bears reach breeding maturity at about 4 or 5 years of age, and breed every 2 to 3 years. Black bears breed in the spring, usually in May and June, but the embryos do not begin to develop until the mother dens in the fall to hibernate through the winter months. However, if food was scarce and the mother has not gained enough fat to sustain herself during hibernation as well as produce cubs, the embryos do not implant (develop). Black bear cubs are generally born in January or February. The blind cubs weigh about 1/2 to 3/4 of a pound at birth, and twins are most common. By spring thaw, when the bears start leaving their dens, the cubs are fur-balls of energy, inquisitive and playful. They are weaned between July and September of their first year, and stay with the mother through the first full winter. They are usually independent by the second winter.
Cub survival is totally dependent on the skill of the mother in teaching her cubs what to eat, where and how to forage (find food), where to den, and when and where to seek shelter from heat or danger. Except for breeding and raising young, black bears are generally solitary animals. They try to avoid humans and are considered non-aggressive except when injured, protecting their young, or protecting themselves. Daily movements are influenced greatly by temperature and food availability. Bears usually feed in the cool of the evening or early morning. During the heat of the day, they will seek shade in dense underbrush. Home ranges are determined by food types, abundance, and availability, and can be as small as 1 square mile or as great as 100 square miles.
Except for females with cubs, black bears spend most of their time alone. During the breeding season, a male and female may remain together for several days at a time in June, July and August and groups of bears may feed in close proximity to each other if food is abundant, such as in berry patches or at dumps. Gestation is 220 days. Cubs are weaned at 8 months, but stay with mother for 1.5 years
Home Range - Female home ranges are 3 to 40 square kilometers (1 to 15 square miles). While the home ranges of individual bears are usually exclusive from those of other bears of the same sex, male home ranges are larger and may overlap those of several females. A young adult female is often allowed to establish her territory within that of her mother, while subadult males must disperse. Characteristically, a home range does not constitute one large area but rather is composed of several smaller food source areas connected by travel lanes. Open areas are usually avoided by black bears as they prefer wooded cover. Found throughout most of Canada, Alaska, south on West Coast through California, in Rocky Mountain states to Mexico, and parts of Minnesota, Wisconsin, Michigan, New England, Florida, Arkansas, Missouri and Louisiana. Black bears (Ursus americanus) originated in Asia. They migrated to North America over time. The current black bear population, world-wide, is approximated at up to 500,000. (1992)
Hibernation - Most black bears, including all who live in areas with severe weather climates, will hibernate for between four and seven months. Where the weather is much more temperate and the period without food available is quite short, black bears may either not hibernate or they may simply nest in a thicket or other sheltered area for brief periods of time. During the entire period of hibernation, the black bear will neither pass urea or solid fecal waste. While urea poisoning causing death would occur in all other animals, bears have developed a unique process of recycling the urea into usable proteins. During the hibernation period, all bears lose a great deal of weight. Adult males and adolescent bears lose between 15% and 30% of their weight while it is not uncommon for a female cub with newborn cubs to have lost as much as 40% of her weight.
Most black bears vacate their winter dens over a one to two month period commencing in April or May. Both the climatic conditions (snow cover and temperature) and physiological factors such as the bear's age, the status of its health and its remaining fat reserves affect the exact timing of emergence from its den. Normally, adult males emerge first. Females with newborn cubs are usually the last to leave their dens.
