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Natural HistoryMammals - LargeGrizzly Bear - Ursus arctos horribilisProfiles
Sense of Life
Everyday Bears

Sense of Life - Continued

Page 3 of 7

Sense of Smell

  • The bear's most important sense, for feeding and defense
  • Equal to, or better than, a dog's. A sheepdog has 220 million olfactory receptors; a human has 5 million.
  • Indian saying: "A pine needle fell in the forest. The eagle saw it. The deer heard it. The bear smelled it."
  • Grizzly's own odor is unique and unforgettable

  • Omnivorous
  • Not a predator of humans; normally does not eat human flesh

  • In Lewis and Clark's era, from Mexico to northern Canada
  • Individual bears: 80 to 100 sq mi, depending on quality of habitat

  • At a lope, 30 miles per hour (44 feet per second)
  • Can run about as fast downhill as uphill

  • Average lifespan, 25 to 30 years

Causes of Mortality
  • Loss of habitat
  • Diseases (internal parasites)
  • Old age (loss of functional teeth; unable to store up enough fat to survive the winter)

  • Generally shy and peaceful, secretive
  • Inquisitive, especially young adults
  • Ferocious when provoked

  • Seems often to learn from a single experience (food source, threat, trap, rifle shot), and remembers the lesson
  • Experiments are being conducted in Montana, Alberta, and Alaska using Karelian dogs, originally bred in Finland to hunt bears, to teach "problem" bears (both grizzlies and black bears) to stay away from humans.

  • Hibernates, but body temperature and metabolism do not diminish much
  • Dormant or inactive for five to seven months, but can awaken and temporarily leave den
  • Do not eat, urinate, or defecate
  • Females give birth in January

--Joseph Mussulman; reviewed by Charles Jonkel

Sense of Life
Everyday Bears

From Discovering Lewis & Clark ®, http://www.lewis-clark.org © 1998-2014
by The Lewis and Clark Fort Mandan Foundation, Washburn, North Dakota.
Journal excerpts are from The Journals of the Lewis and Clark Expedition, edited by Gary E. Moulton
13 vols. (Lincoln: University of Nebraska Press, 1983-2001)