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.
Bears are omnivores. They eat both plants and animals, but mostly plants. Their
diet varies with their habitat, but typically includes berries, grasses and
herbs, insects, small mammals, and carrion. It's a myth that bears eat only
scavenged meat. Bears are known to sometimes kill and eat newborn or young
animals such as fawns, rabbits, or birds. The black bear's most reliable source
of protein and fat is ant pupae.
Bears love honey.
Bears sometimes hibernate in caves, but more often they burrow into the ground
and build dens. The passage usually angles down into the ground and may turn
a corner. The den is fairly snug, giving the bear about 8 to 10 inches on either
side of her body when she crawls in.
The body temperature of a hibernating bear will drop from its usual 100 degrees
to 88 degrees F. The bear's heart will slow from 60 to 100 beats a minute down
to 20 to 40 beats or even fewer. Instead of its usual 15 to 20 breaths per
minute, a hibernating bear may take one deep breath every 45 seconds.
Not all American black bears are black. Some are dark brown. Cinnamon colored
bears are common west of the Mississippi River.
Some people think bears smell bad, but bear expert Dr. Lynn Rogers says the
most common bear odor is clean and pleasant, even after six months in a den.
A black bear has round ears, small eyes, and a long snout. It has a heavy body,
short tail, and plantigrade feet--that is, both heel and toe make contact with
the ground when walking in a manner similar to humans. Their hind feet have
five toes.
All black bears are agile tree climbers. Their curved claws help them grasp
the tree bark. (Grizzly bears are not climbers.)
Females, or sows, generally weigh about 200 to 300 pounds. Males, or boars,
weigh 250 to 600 pounds.
Like other bears, black bears have better eyesight than most people give them
credit for. They also have keen hearing. But their sense of smell is their
keenest sense.
Some people think black bears are unpredictable and dangerous. The truth is
that people have little to fear from black bears. These bears are wary of humans.
(Grizzly bears can be unpredictable and more likely to attack.)
Black bears have a lumbering walk, but they can run much faster than people.
They have been known to run faster than 40 kilometers per hour (over 25 miles
per hour) for short distances. (Grizzlies run faster than black bears, but
black bears can climb trees to escape grizzlies.)
Dr. Lynn Rogers
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Some people have the mistaken idea that when a bear charges,
it's time to shoot. Dr. Lynn Rogers has studied black bears for many years.
He
says black bear charges are pure bluff. "Hold your ground, or better yet,make
noise and wave your arms, and the bear will go back to its business. But
NEVER challenge a bear that's cornered," says Dr. Rogers.
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.
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