How does a bear know that it's time to hibernate?
The bear is alerted in part by hormonal changes that alter its
bodily functions. But scientists have not proven exactly what
triggers the hormones that encourage hibernation * whether it's
the shorter days, the feeling of coldness in the air, or the
scarcity of food. Bears hibernate to conserve energy during a
time when their habitats produce little in the way of food or
water.
What happens to the bear's body during hibernation?
The bear sleeps, without food, for a long time. In the southern
Appalachian Mountains, the black bear will generally sleep from
December through March and can sleep longer, up to seven months.
Bears prepare for hibernation in the fall, eating generously and
putting on about 100 extra pounds, which they will gradually lose
during the months of hibernation. During hibernation itself, the
bear's digestive system stops and the accumulated body fat
provides the only nourishment. Scientists do not fully understand
how bears break down their body wastes and convert them back into
protein. It's also unclear how their bodies manage the large
amounts of cholesterol that build up during hibernation. The
bear's normal heart rate of about 80 heart beats per minute drops
to just 8 beats per minute. The bear's thick fur keeps its body
temperature just a few degrees below normal.
How deeply do bears sleep when in hibernation?
Surprisingly, the bear's sleep is relatively light and he can be
awakened by even a small disturbance. (Remember that if you think
about going into a bear's den in winter.) Their hibernation might
be better thought of as very long naps -- a bear can doze for
weeks at a time -- than a single unbroken sleep. Here's the real
shocker, though. Black bears give birth to one to four cubs
during hibernation, generally in January or February. The young
cubs are born weighing less than a pound and are nourished by
their slumbering mother's milk. By the time spring comes, they
may weigh as much as eight pounds.
Animal Posters
Paralumun New Age Village