Facts About Black Bears
Ursus americanus "American bear" is
the name scientists gave the black bear. Some people call it the American
black bear to distinguish
it from the Asian black bear, a different species.
Female black bears normally mature at 3 to 5 years of age. Some wait even longer until their first mating.
Females will normally mate with several males over the two to three weeks of the breeding season. Black bears usually breed every other year.
Through a remarkable process called delayed implantation, the fertilized ovum divides a few times and then floats free within the uterus for about six months without further development. Sometime around the denning period, the embryo will attach itself to the uterine wall and after a period of eight weeks (sometime in January or February), the cubs will be born while the mother is in hibernation.
Delayed implantation serves an important survival need for the mother. If she does not have enough fat reserves to carry her through the winter, the embryo will not implant and grow. It is simply reabsorbed by her body.
Black bears usually mate in May or June, though bears in more northern areas may mate as late as August. After they mate, the male leaves the female. As winter approaches, the female puts on fat that will feed both her and her unborn young.
After entering the den, the female falls into a deep sleep. The cubs are usually born in January and February, often while the female is still hibernating. Two or three cubs are typical, although she may give birth to just one--or as many as five. Climate and food supply are important determinants of the size of the litter.
The tiny young are born blind and almost hairless. They finish their development in the weeks after birth, nourished on rich mother's milk. The family may remain in the den until May. Hibernation usually ends earlier in warmer, more southern regions.
On rich mother's milk that contains over 20 percent fat, the babies develop quickly. They will be able to follow their mother when she leaves the den as soon as 5-8 weeks after their birth. By then the babies weigh about 7 pounds, the size of a human baby at birth.
The cubs grow fat on their mother's milk until they are weaned, usually at about six to eight months of age. They stay with the mother and spend a second winter with her in hibernation. During their second spring, they usually leave and strike out to live the more solitary life of an adult.
Bear cubs face many predators. Adult male bears quite commonly eat cubs. Wolves, bobcats, eagles, mountain lions and, dog packs (in more urban areas) have been known to kill young cubs who become separated from their mother's side.
Some people think that a mother black bear will fight to the death in defense of her cubs. Researcher Dr. Lynn Rogers has found this to be a myth. He often chases black bear families to tree and tag the cubs. In many cases the mother keeps running, stops nearby and waits or just bluff-charges--even as the cubs cry "maa, maa," in a remarkably human-like voice.
The black bear's habitat has been severely encroached upon by human communities and farming. Humans are serious predators of bears; hunters pursue them for sport, and in some places, farmers view bears as nuisance pests to be killed.
Black bear range extends from the northern tree limit of the Arctic far to the south, through most of Canada and the United States. Black bears are found as far south as the range of the Sierra Madre Mountains in north-western Mexico. This area includes 37 American states, all the provinces and territories of Canada except Prince Edward Island, and 5 Mexican states. In North America, black bears have a bigger range than grizzy bears.
Black bears lack the distinct shoulder hump of the brown/grizzly bear. The claws on the front paws are much shorter than a grizzly's and generally not visible from a distance.
Every adult bear has an individual territory. Part of that territory is the bear's exclusive domain, but it also shares part with other bears. The territory is composed of several smaller food source areas connected by travel lanes. In general, female black bears will have a home range of 6.5 to 26 square kilometers (2 1/2 to 10 square miles), while males will normally have a home range which is four times larger at 26 to 124 square kilometers (10 to 40 square miles). The home range of a mature male bear will often overlap the home range of several female bears.
Black bears prefer wooded cover and usually avoid open areas. They often use stream and creek beds as travel lanes because this avoids thick undergrowth and provides a barrier-free escape route. This is particularly true in areas where there is heavy urban build-up.
Black bears are the most widely found and most numerous kind of bear in North America. Black bears come into contact with more humans than almost any other species of bear. This is the one bear species that seems able to survive in populated areas.
Black bears in the wild can live twenty-five years or more. Most of them live only about five years because of hunting and human encroachment into their habitat.
In Florida and other southern states, black bears don't hibernate. But most bears find or dig an earthen den in which to rest and bear their young. Bears in southeastern states usually den in tree cavities.
Although black bears very seldom attack people, they are still feared and hated by some people. Black bears are protected by laws, but are hunted for sport in some states. Other bears are poached, often to supply parts to the Asian folk medicine trade. But the greatest threat to black bears is habitat loss as people continue to multiply and invade its territory.
Probably the most famous black bear lived in Louisiana. It was a black bear cub that big game hunter Theodore Roosevelt (a U.S. President) refused to shoot. It inspired the stuffed toys known today as "teddy bears."
Another famous black bear was rescued from a forest fire in New Mexico. It became known as Smokey Bear. New Mexico chose the black bear as its state animal. The black bear also represents West Virginia, and Ontario's coat of arms has a black bear in the design.