Hibernation is a state
of dormancy and inactivity used by bears and various
other animals to adapt to short winter food supplies.
"Hibernation is not so much a response
to extreme cold as to a seasonal shortage of food,"
notes Paul Schullery in The Bears of Yellowstone.
"The bear's warm coat is as necessary
to it in the den as it would be outside."
Hibernation of bears is different from other
"hibernators" such as bats, marmots,
squirrels, woodchucks and rodents that are in
a deep sleep or state of torpidity, with a low
metabolic rate and temperatures many degrees
below normal. Several weeks are required
to reach that state of dormancy.
During a bear's hibernation, its body temperature
does not drop to within a few degrees of the
surrounding air; its metabolic rate is
comparatively high, and it may awaken during
a warm period and move about outside the den,
though it remains nearby.
Specific lengths of hibernation depend on climate,
location, and the sex, age group, and reproductive
status of the individual bear. Some bear(s)
... do not hibernate ... in areas of available
foods and warm winter weather. Bears in
poor condition, with an inadequate fat reserve,
may not hibernate or for only a short period.
Hibernating bears:
Do not eat
Do not urinate
Do not defecate
Curl up to conserve heat
Change position in the den
Are sensitive to surroundings
Awaken and move about
Temporarily leave den
May be aroused and attack an intruder
Give birth to young
Lactate (nurse their young)
Provide warmth for cubs
Lick and groom cubs
Lick self
Slough paw pads
Lose weight
--all information on this page is provided
by the Kodiak National Wildlife Refuge (portions
adapted from The Great Bear Almanac,
Brown)
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