American Black Bears
Meet Mogie & Blue (m), born January 2016
Species: Ursus americanus
Mogie and Blue were rescued as young cubs after their mother was killed at the Blue Ridge Reservoir, located in Arizona’s scenic Mongolian Rim area. Too young to survive without a sow, they were picked up by the Arizona Department of Game and Fish. The cubs were then relocated to their permanent home at Out of Africa Wildlife Park. They warmed up to park staff and visitors surprisingly fast. As with all young bear cubs, they are highly food-motivated and always playful. Mogie is brown in color while Blue sports a black coat. These two siblings each display wonderful and unique personalities in very entertaining fashion.
The American black bear is distributed throughout North America, from Canada to Mexico and in at least 40 states in the U.S. They historically occupied nearly all of the forested regions of North America. In the U.S. they are restricted to the forested areas less densely occupied by humans. In Canada, black bears still inhabit most of their historic range except for the intensively farmed areas of the central plains. In Mexico, black bears were thought to have inhabited the mountainous regions of the northern states but are now limited to a few remnant populations.
The skulls of American black bears are broad with narrow muzzles and large jaw hinges. Females tend to have more slender and pointed faces than males. Their claws are typically black or grayish brown and short and rounded, being thick at the base and tapering to a point. Claws from both hind and front legs are almost identical in length—about 1 ½ inches. The relatively short claws enable the black bear to climb trees with ease.
Black bears are highly dexterous, capable of opening screw-top jars and manipulating door latches. They also have great physical strength. Even bear cubs have been known to turn over flat-shaped rocks weighing 310 to 325 pounds by flipping them over with a single foreleg. They move in a rhythmic, sure-footed way and can run at speeds of 25 to 30 mph. Black bears have good eyesight and have been proven experimentally to be able to learn visual discrimination tasks based on color faster than chimpanzees and as fast as dogs. They are also capable of rapidly learning to distinguish different shapes, such as small triangles, circles, and squares.
Black bear weight tends to vary according to age, sex, health, and season. Seasonal variation in weight is very pronounced: in autumn, their pre-den weight tends to be 30% higher than in spring, when black bears emerge from their dens. Adult males typically weigh between 126 and 551 pounds, while females weigh 33% less at 90 to 375 pounds.
The fur is soft with dense under-fur and long, coarse, thick guard hairs. The fur is not as shaggy or coarse as that of brown bears. American black bear skins can be distinguished from those of Asiatic black bears by the lack of a white mark on the chin and hairier footpads. Despite their name, black bears show a great deal of color variation. Individual coat colors can range from white, blond, cinnamon, or light brown to dark chocolate brown or jet-black, with many intermediate variations existing.
The average lifespan in the wild is 18 years, though it is quite possible for wild specimens to survive for more than 23 years. The record age of a wild specimen was 31 years, while that in captivity was 44 years. Typically, black bears will live up to 35 years in captivity.
Sows, or females, usually produce their first litter at the age of 3 to 5 years. Sows living in more developed areas tend to get pregnant at younger ages. The breeding period usually occurs in the June-July period, though it can extend to August in the species’ northern range. The breeding period lasts for 2 to 3 months. Both sexes are promiscuous. Males try to mate with several females, but large, dominant ones may violently claim a female if another mature male comes near. Sows tend to be short tempered with their mates after copulating. The fertilized eggs undergo delayed development and do not implant in the female’s womb until November. The gestation period lasts 235 days, and litters are usually born in late January to early February. Litter size is between 1 and 6 cubs, typically 2 or 3. At birth, cubs weigh less than a pound and measure 8 inches in length. They are born with fine, gray, down-like hair, and their hind quarters are underdeveloped. They typically open their eyes after 28 to 40 days and begin walking after 5 weeks. Cubs are dependent on their mother’s milk for 30 weeks and will reach independence at 16 to 18 months. At the age of 6 weeks, they attain 2 pounds, by 8 weeks they reach 5 to 6 pounds, and by the age of 6 months they weigh 40 to 60 pounds. They reach sexual maturity at the age of 3 years and attain their full growth at 5 years.
Black bears are extremely adaptable and show a great variation in habitat types, though they are primarily found in forested areas with thick ground vegetation and an abundance of fruits, nuts, and vegetation. In the northern areas, they can be found in the tundra, and they will sometimes forage in fields or meadows.
Black bears tend to be solitary animals, with the exception of mothers and cubs. The bears usually forage alone but will tolerate each other and forage in groups if there is an abundance of food in one area.
Most black bears hibernate depending on local weather conditions and availability of food during the winter months. In regions where there is a consistent food supply and warmer weather throughout the winter, bears may not hibernate at all or do so for a very brief time. Females give birth and usually remain denned throughout the winter, but males and females without young may leave their dens from time to time during winter months.
Unlike true hibernating animals whose body temperatures plummet past freezing, bear temperatures only drop about 10 degrees while they “den” during winter.
Black bears are very opportunistic eaters. Most of their diet consists of grasses, roots, berries, and insects. In northern regions, they eat spawning salmon. They will also eat fish and mammals—including carrion—and easily develop a taste for human foods and garbage. Bears who become habituated to human food at campsites, cabins, or rural homes can become dangerous and are often killed—thus the frequent reminder: Please don’t feed the bears!
- Like all bears, the American black bears are good climbers and swimmers.
- While bear attacks on humans are extremely rare, bears are very strong and powerful animals; they should always be treated with caution and respect.
- Black bears are not true hibernators. During their winter dormant period, though, they do not eat, drink, urinate, or defecate but may wake up if disturbed.
- Bears are bowlegged. This gives them better grip and balance.
- The most accurate way to determine the age of a bear is to count the rings in a cross section of its tooth root under a microscope.
- Only the polar bear is a true carnivore. All other bears are omnivores, or animals that eat both plants and meat.
- Koala bears are not bears at all and are not related to the bear family. They are marsupials.
Ecology and Conservation:
The American black bear is listed by the IUCN as Least Concern, due to the species’ widespread distribution and a large global population estimated to be twice that of all other bear species combined. Along with the brown bear, it is one of only 2 of the 8 modern bear species not considered globally threatened with extinction by the IUCN.