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Folklore: Perhaps no other animals have so excited
the human imagination as bears. References to bears are found in ancient and
modern literature, folk songs, legends, mythology, children stories, and
cartoons. Bears are among the first animals that children learn to recognize.
Bear folklore is confusing because it is based on caricatures, with Teddy Bears
and the kindly Smoky on one hand and ferocious magazine cover drawings on the
other. Dominant themes of our folklore are fear of the unknown and man
against nature, and bears have traditionally been portrayed as the villains to
support those themes, unfairly demonizing them to the public. A problem for
black bears is that literature about bears often does not separate black bears
from grizzly bears.
General Description: The black bear is approximately
4 to 7 feet from nose to tail, and two to three feet high at the withers. It
has small eyes, rounded ears, a long snout, a large body, a short tail, and
shaggy hair. It differs from grizzly bears in being smaller with a
smaller shoulder hump, a furred rear instep, a less concave facial profile,
smaller claws that are more tightly curved, and longer, smoother, and more
tapered ears.
Classification of Ursus americanus, the American black
bear: Kingdom: Animal, Phylum: Chordata, Class: Mammalia, Subclass: Theria, Infraclass:
Eutheria, Order: Carnivora, Suborder: Fissipedia, Family: Ursidae, Subfamily: Ursinae (all bears except the giant
panda and the spectacled bears), Genus: Ursus, Subgenus:
Euarctos, Species: americanus.
Taxonomists generally separate black bears into 16
subspecies based on minor differences in appearance and DNA. : Ursus americanus
altifrontalis (Pacific Northwest), U. a. amblyceps (Southwestern US), U. a.
americanus (widespread from Alaska to the Atlantic), U. a. californiensis
(interior California), U. a. carlottae (Queen Charlotte islands of British
Columbia), U. a. cinnamomum (WY, eastern CO, ID, western MT, southwestern
Alberta, southeastern British Columbia), U. a. emmonsii (coastal AK from
Glacier Bay to Prince William Sound), U. a. eremicus (northeastern Mexico and
the Big Bend area of Texas), U. a. floridanus (FL, southern GA, southern AL),
U. a. hamiltoni (Newfoundland), U. a. kermodei (portion of coastal BC), U. a.
luteolus (southern LA, and southern MS), U. a. machetes (northwestern Mexico),
U. a. perniger (Kenai Peninsula of AK), U. a. pugnax (southeastern Alaska), U.
a. vancouveri (Vancouver Island). Taxonomists update subspecies
classifications as they learn more about regional differences in DNA, body
form, and behavior.
Names: Some black bear subspecies go by different
names, like Kermode bear, Cinnamon bear, or Glacier bear, but they are all
black bears. We prefer calling male and female bears simply males
and females, but many people call them boars and sows, like pigs.
Although pigs and black bears are both omnivores, they are not related. A
group of bears is sometimes called a sloth of bears after the Middle English slowthe,
meaning slow. The term is inaccurate because bears are not slow (see
below), and few people use the term anymore.
Range: The American black bear is found only in North
America. The population is estimated at 750,000. They live
in forests as far south as Florida
and northern Mexico
and as far north as forests grow in Alaska
and Canada.
In northern Labrador, where grizzly bears no longer live, black bears range out
onto open tundra where there are no trees to escape into. People are
becoming more tolerant of black bears as we learn more about them. Many
people are enjoying having bears live close to them where the bears were once
feared and killed.
Color: Body fur usually black or brown but
occasionally blonde, or rarely white as in the Kermode subspecies of coastal British
Columbia. Brown muzzle. White chest patch
is uncommon in most populations. Eyes brown (blue at birth). Skin
light gray.
Adult Weights: Wild male black bears of breeding age
usually weigh between 125 and 500 pounds, depending upon age, season, and
food. Very well fed bears can be heavier. The record is 880 pounds
in Craven County, North Carolina,
and a close second from northeastern Minnesota
weighed 876 pounds on September 5, 1994.
Wild females usually weigh between 90 and 300 pounds with the heaviest known
female weighing 520 pounds in northeastern Minnesota
on August 30, 1993.
Black bears in captivity may exceed these records.
Adult Length: 50 to 80 inches long, nose to tail,
with males being larger than females.
Mating Season: Usually from late May to early
July. In the eastern deciduous forest, mating season can extend into
August.
Implantation: Delayed until November.
Birth: January or early February.
Number of Cubs: The number of cubs in a litter is
usually 2 in the western United States
and 3 in the eastern United States.
First litters are often only 1 or 2. Litters of 6 have been reported in
several eastern states.
Birth Weight: Cubs weigh 1/2 to 1 pound at birth.
Fall Weight of Cubs: By their first fall, cubs may
weigh as little as 15 pounds or more than 165 pounds, depending on food supply.
Parental Care: Cubs usually stay with their mother
for 17 months (rarely 29 months). One to six days before the mothers are
ready to mate in late May or June, they force their yearlings to stop traveling
with them.
Age at Production of First Cubs: 2 to 11 years,
depending upon food supply. Typically 3 to 7 years.
Interval Between Litters: Typically 2 years, but it
can be 3 or 4 years if food is so scarce that they have to abort their
blastocysts, embryos, or fetuses. If a litter is born but dies before the
mating season, the mother will mate again and produce cubs in consecutive
years.
Sex Ratio: Nearly 50:50 at birth. Males are
killed by people at a higher rate, though, so the sex ratio among mature bears
is often one male per 2-5 females.
Vision: Bears see in color and have good vision
close-up. Their distance vision (over two hundred yards) has not been
tested.
Hearing: Exceeds human frequency ranges and probably
twice the sensitivity.
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.
Sounds: 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.
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.
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.
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.
Do bears hibernate? When hibernation was
defined simply in terms of temperature reduction, bears were not considered
hibernators. New knowledge of hibernation processes has led biologists to
redefine mammalian hibernation as simply a specialized, seasonal reduction of
metabolism concurrent with the environmental pressures of scarce food and low
ambient temperatures. Black bears are now considered highly efficient
hibernators. They sleep for months without eating, drinking, urinating,
or defecating. Hibernators with lower body temperatures, such as
chipmunks, woodchucks, and ground squirrels, cannot do this. These
smaller mammals must awaken every few days, raise their temperatures to over 94
degrees, move around in their burrows, and urinate. Some of them must
also eat and defecate during arousals. Black bears have far more
insulative pelts and have lower surface to mass ratios than the smaller
hibernators. As a result, bears' body heat is lost very slowly, enabling
them to cut their metabolic rate in half and still make it through winter,
maintaining temperatures above 88 degrees--within 12 degrees of their normal
summer temperature. (Excerpted from "A Bear
In Its Lair" by Lynn Rogers, Natural
History Magazine, October 1981). Mothers wake up to give birth, typically
in mid to late January, and take excellent care of the cubs in the den, licking
them clean and responding to every cry for warmth and milk.
Length of Hibernation: The length and depth of
hibernation is genetically programmed to match the regional norms of food
availability. Hibernation is deeper and can last over 7 months in the
northern portion of the black bear range where abundant, high quality food is
available only from May through August. There, some bears hibernate so
deeply, especially the leaner bears after a summer of unusually scarce
food, that a person can jostle them for several minutes before they wake
up. However, in southern states where food is available year-round, some do
not hibernate at all, and those that do are easily aroused. Lean females
cannot bring their fetuses to full term and do not give birth.
Potential Longevity (lifespan): Black bears can live
21-33 years or more if they are not killed.
Causes of Death: Very few adult bears outside of
national parks die of natural causes. Nearly all adult bears die from
human-related causes. Most are eventually shot. A few are killed by
vehicles. The average age of death in hunted populations is three to five
years of age. Bears less than 17 months old sometimes die from
starvation, predation, falls from trees, and other accidental causes.
Very few die of disease.
Core Home Range Diameter: Typically: Yearlings: 1-2
miles. Adult females: 2-6 miles. Adult males: 8-15 miles. Excursions to 126
miles recorded.
Ideal Habitat: Black bears like large forests with
many different kinds of fruits and nuts. Small sunny openings within the
forest provide many kinds of food for the bears. Lowlands
and wetlands provide tender and juicy vegetation. Streams and woodland
pools provide water for drinking and cooling. Mothers with cubs like
large trees (over 20 inches in diameter) with furrowed bark (like white pines
or hemlocks) for bedding sites. These trees are safest for small cubs to
climb.
Living with Bears: Many people are moving into black
bear habitat. The bears' future depends on how well we understand and
tolerate them.
Long-Term Problem: Magazines and movies have given
black bears an unrealistically ferocious image, causing people to fear them
excessively and kill them unnecessarily. There are many misconceptions
about black bears.
Greatest misconception: The greatest misconception
about black bears is that they are likely to attack people in defense of
cubs. They are highly unlikely to do this. Black bear researchers
often capture screaming cubs in the presence of bluff-charging mothers with no
attacks.
Defense of cubs is a grizzly bear trait. About 70
percent of human deaths from grizzly bears are from mothers defending cubs, but
black bear mothers have not been known to kill anyone in defense of cubs.
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