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Bears
The bear family, Ursidae, consists of 9 species. Until recently, giant
pandas and red pandas were classified as members of the raccoon family,
but DNA studies in the 1980s established that pandas were more closely
related to bears. Some scientists believe that the giant panda and the red
panda should be placed in their own family, the Ailuropodidae.
Bears are found on all continents except Australia and Antarctica. Most
bears are solitary and omnivorous which means that they feed on a variety
of foods, including animal and plant matter. They tend to move slowly but
are very capable of running fast if necessary.
Some bear species undergo a period of deep sleep over the winter, when
food is scarce. This phase is not true hibernation because the body
temperature only drops a few degrees and the bear is capable of quick
arousal. During this time they do not eat, drink, e or defecate. Before
entering the den they must fatten themselves up (their body weight may
double) and the fat is broken down as fuel. Pregnant females may give
birth at this time, when the cubs are safe within the den.
Most species of bear undergo a period of delayed implantation during
reproduction; the fertilised egg floats around in the uterus for several
months before attaching itself to the wall of the uterus and beginning
development. This enables the female to give birth to her cubs at the most
suitable time. If food availability is poor, the embryo is reabsorbed by
the mother's body.
Unlike other carnivores, which walk on the tips of their toes (digitigrade
gait), bears walk on the soles of their feet (plantigrade gait) as humans
do.
Bears have an aggressive reputation, but in most cases this is undeserved.
Information provided by: BBC Online..Nature & Wild Animal Facts
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