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Brown Bear (Ursus arctos) Fact Sheet: Diet & Feeding

Diet & Feeding

Omnivorous

North American brown bears once thought to only be scavengers (before scientists use satellite telemetry to track movements).

Recent studies show a more carnivorous diet than more omnivorous American and Asiatic Black Bears, Sun Bears, and Andean Bears. (Sacco and Van Valkenburgh 2004)

  • Prey: typically juvenile ungulates and small, burrowing rodents.
    • Extreme size difference with prey - may be up to 100 times heavier than prey
    • Use brute strength rather than specialized killing techniques to dispatch prey
    • In Mt. McKinley National Park, bears ate voles, lemmings, mice, ground squirrel. (Murie 1985)
    • On Tibetan Plateau, eat mainly meat; pika are the prey. (Xu et al 2006)
  • Have the capacity to also take much larger prey such as moose, musk oxen, caribou, elk. pronghorn, deer, bison (Murie 1985) (Craighead 1995) (Mowat & Heard 2006)
    • Calves are preferred but adults sometimes taken (Zager and Beecham 2006)
    • Caribou in Arctic provide significant portion of terrestrial meat (not salmon) in diet
  • Salmon important component of diet in Pacific coast of North America. (Mowat & Heard 2006) (Zager and Beecham 2006)
    • In coastal areas, salmon provide the main source (greater than 50%) of nutrients for Brown Bears.
  • Seasonal changes in metabolism (Hilderbrand et al 1999)
    • In spring bears convert meat to lean body mass
    • In fall, bears convert excess protein to fat

In addition to carnivorous habits, consume a wide variety of plant and animals, seasonally available (Craighead 1995) (Murie 1985) (White et al 1998)

  • Berries, Whitebark Pine seeds in Yellowstone ecosystem (important for laying on stores of fat for winter)
  • Sedges, grasses, horsetail (Equisetum)
  • Dig and eat underground stores of roots and tubers cached by mice.
  • Army cutworm moths (noctuids) sought on high mountain rocky slopes.
  • Honey
  • In Yellowstone region, Whitebark Pine trees currently severely threatened by disease and a warming climate; major concern for grizzly well-being.(Mattson & Merrill 2002).

Search for food with a wide variety of techniques, using "intelligence, curiosity, determination, skills, memory and endurance" (Huber 2010)

  • Turning over rocks
  • Plucking rotten logs and anthills (for ants)
  • Digging for tubers and invertebrates
  • Catching for small mammals
  • Stalking and capturing ungulates

After having eaten its fill, bear may cache remaining carcass by covering it with soil, sod, or rocks.

  • Largest bears have priority when a carcass is discovered; subordinate bears wait

Page Citations

Craighead (1995)
Hilderbrand et al (1999)
Mattson & Merrill (2002)
Mowat & Heard (2006)
Murie (1985)
Sacco and Van Valkenburgh (2004)
White et al (1998)
Xu et al (2006)
Zager and Beecham (2006)

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