A bear is a large mammal of the order Carnivora, family Ursidae.
Common characteristics of bears include a short tail, excellent
senses of smell and hearing, five un-retractable claws per paw,
and long, dense, shaggy fur.
Bears have a large body with powerful limbs. They are capable of
standing up on their hind legs. They have broad paws, long snouts,
and round ears. Their teeth are used for defense and tools and depend
on the diet of the bear. Their claws are used for ripping, digging,
and catching. A bear's eyesight is probably similar in acuity (sharpness)
to the human eye. Black bears, and likely other bears, have color
vision to help them identify fruits and nuts.
Depending on the species, bears can have 32 to 42 teeth. Bear teeth
are not specialized for killing their prey like those of cats. Normal
canine teeth in a carnivore are generally large and pointed used
for killing prey, while bears' canine teeth are relatively small
and typically used in defense or as tools. Bears' molar teeth are
broad, flat and are used to shred and grind plant food into small
Bears have four limbs that end in paws. Each paw has five long,
sharp claws that are unretractible, unlike cats. These claws can
be used to climb trees, rip open termite nests and beehives, dig
up roots, or catch prey, depending on the species. While most carnivores
tend to walk on their toes in a way that is adapted for speed, bears
have a plantigrade stance. They walk with their weight on the soles
of their hindfeet, with the heel touching the ground, while the
toes of the forefeet are used more for balance. Although slower
than most carnivores, a running bear can reach speeds of up to 50
km/h (30 mph). They are also stronger than most carnivores and their
limbs are more flexible and agile.
A bear's fur is long and shaggy. Fur color varies among species,
ranging from white, blonde or cream, black and white, to all black
or all brown. Colors of a bear's fur can also vary within species.
For example, American black bears may be black, brown, reddish-brown,
or bluish-black. Several species, such as the sun bear and spectacled
bear have a light-colored chest with facial markings.
In all bear species, males are larger than females, but the difference
between sexes varies and is greatest in the largest species. Large
male polar bears may weigh twice as much as females, while smaller
male and female bears are much more similar in weight. A bear's
life span seems to last about 25 to 40 years. Bears living in the
wild tend to die younger than their zoo-counterparts.
Bears live in a variety of habitats from the tropics to the Arctic
and from forests to snowfields. They are mainly omnivorous, although
some have a more specialised diet, such as polar bears. They eat
lichens, roots, nuts, and berries. They can also go to a river or
other body of water to capture fish. Bears will commonly travel
far for food. Hunting times are usually in the dusk or the dawn
except when humans are nearby.
Bears mostly live alone, except for mothers and their cubs, or
males and females during mating season. Bears form temporary groups
only when food is plentiful in a small area. Alaskan brown bears
group in the same area to feed on salmon during the annual salmon
runs, when the fish swim upriver to reach their spawning grounds.
Other bears may live alone but exist in a social network. A male
and female may live in an overlapping home range, each defending
their range from other bears of the same sex. Male young usually
leave their mothers to live in other areas, but females often live
in an area that overlaps that of their mother.
Bears travel over large territories in search of food, remembering
the details of the landscape they cover. They use their excellent
memories to return to locations where food was plentiful in past
years or seasons. Most bears are able to climb trees to chase prey
or gain access to additional vegetation. The only exceptions are
polar bears and large adult brown bears, whose heavy weight makes
it difficult to climb trees.
Some of the large species, such as the polar bear and the grizzly
bear, are dangerous to humans, especially in areas where they have
become used to people. For the most part, bears are shy and are
easily frightened of humans. They will, however, defend their cubs
The bear's courtship period is very brief. Bears reproduce seasonally,
usually after a period of inactivity similar to hibernation. Cubs
come out toothless, blind, and bald. The cubs, usually born in litters
of 13, will stay with the mother for six months. They will
be fed by milk at first and will start hunting with the mother in
three months. Then, they are weaned. However, they will still remain
nearby for three years. The cubs reach sexual maturity at seven
years. Normally, bears are very solitary and will not remain close
together for long periods of time.
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