Hibernation of the Black and Brown Bear : Hibernation of the Black and Brown Bear Bobby Bennett
Winter Ecology Field Course
Spring 2006
Mountain Research Station
University of Colorado, Boulder
Typical Hibernation Patterns : Typical Hibernation Patterns Bears do not feed for 7 months, living off body fat until late spring.
They rely of their fur for insulation, which doubles its insulation capacity in winter
They construct some sort of den
Both sexes have a 99% survival rate in winter (Heinrich, p.76)
Hibernation Metabolic Processes of Both Species : Hibernation Metabolic Processes of Both Species Heart rate may decline to 8 beat/min
Leptin, a hormone, controls appetite during hibernation
A Satiety (Heinrich, p.256)
Body temps drop to 35 degrees (37-38 when active)
Doesn’t characterize bears hibernation
Other Bodily Processes : Other Bodily Processes Water balance
They usually do not urinate during the winter
Nitrogen wastes biochemically recycle back into proteins as to not poison the bear
This also prevents muscle mass loss due to no exercise (Heinrich, p.259)
Black and Brown Differences? : Black and Brown Differences? Black Bear
“Easily food conditioned; extremely clever, creature of habit; inquisitive; playful” (Brown, p.94)
Brown Bear
“Dignified; deliberate, fearless, bold, generally peaceful; solitary” (Brown, p.94)
Hibernation Differences : Hibernation Differences Black Bear
Adds 4 in. of fat prior to hibernation
Dens under large boulders, scraped out depressions under brush, in tree routes, caves, under logs, possible in trees, under buildings
20% steep slope
(Brown, p.150) Brown Bear
Adds 6-8 in. of fat prior to hibernation
Dens dug in dry earth, under large boulders, located above valley floor
30% steep slope
Slope aspect depends of exposure
61% on north slope in Rocky Mnts.
(Brown, p.150)
Hibernation Differences Cont. : Hibernation Differences Cont.
Brown bear hibernates as early as September in northern regions
Black bears may not even hibernate during mild winters
(Brown, p.145)
conclusion : conclusion Brown Bear and Black Bear have very similar hibernation patterns despite geographic ranges
The proportionally larger Brown Bear packs on more fat prior to hibernation
There are differences in den characteristics for both species
But… as far as my research has led me, both bears have very similar hibernation/winter-time physiology and behavioral characteristics
What’s Next? Even More Research
Bibliography : Bibliography Brown, G. (1993). The Great Bear Almanac. Lyons & Burford, Publishers.
Heinrich, B. (2003). Winter World: The Ingenuity of Animal Survival, First Ed. HarperCollins Publishers Inc.
Laycock, G. (1986). The Wild Bears. Outdoor Life Books.
Manning, A., Dawkins, M.S. (1992). Animal Behavior, Fourth Ed. Cambridge University Press.