Grizzlies: the Bear Facts

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Grizzlies the Bear Facts

• Grizzly Bear (or Brown Bear)
• Ursus arctos horribilis

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Where Were Going

• Comparisons with other Bears
• Bear Natural History
• Population Status
• Conservation of the Grizzly

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Only 8 species of bears
Polar bear
Brown bear
Giant Panda
Asiatic Black Bear
Sloth Bear
Sun Bear
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Only 8 species of bears
Polar Bear
Brown bear
Black Bear
Spectacled Bear
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North American Bears
Species
Subspecies
Brown Bear
Kodiak Bear (Alaskan islands)
Grizzly Bear (North America)
Polar Bear
Black Bear
Different color morphs
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North American Bears

• Brown bear or Grizzly

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North American Bears

• Black Bear

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North American Bears

• Polar Bear

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Grizzly Size and Range

• One of largest North American land mammals and
  largest terrestrial predator
• Historic range from mid-plains westward to
  California and from C. Mexico north throughout
  Alaska Canada

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Current and Historical Range

• Now, found on only 1 of its original range in
  the lower 48 states
• Last grizzly in California killed in 1922 - now
  only on state flag

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Habitat

• Can survive only where there is spacious habitat
  insulated from excessive human disturbance
• Seem to prefer high elevation alpine and
  subalpine meadow habitat for much of the year
• Occur in a variety of coniferous forest zones

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Grizzly Habitat
Subalpine and alpine habitat in the Beartooth
Mts, Montana
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Diet

• Omnivorous mostly plant material (80-90) but
  also eat other animals, including calf elk and
  moose, insects, and carrion - salmon important
  for coastal populations
• Wild fruits, berries (huckleberry) and plant
  roots and tubers

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Grizzlies and Salmon

• Salmon returning to streams to spawn on Pacific
  coast are consumed by grizzlies
• When salmon easy to catch, bears dont always
  consume all of fish
• humpbacks of males
• bellies of females (eggs!)
• salmon just arriving
• more nutritious

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Grizzlies and Salmon

• Fish remains available to other birds and mammals
• Nutrients excreted by bears (mainly N) then
  available to terrestrial plants
• Bear populations that eat more salmon have
  heavier females, larger litter sizes, and denser
  populations (Hilderbrand 1999)

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Reproduction

• Minimum breeding age 4 1/2 years
• Litter size 1-3 young
• Females usually give birth every 3 years
• Cubs born in den, grow on mothers milk for 1
  year

• Cubs stay with mother for 2-3 years

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Reproduction

• Delayed implantation-- discontinuous embryonic
  development. Some development occurs after
  conception but then it stops for a length of time
  and then resumes.
• Fertilization in May-July (mating season)
• Female starts to hibernate in October-November,
  embryo starts to develop

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Ranges and Movement

• Movement affected by-
• omnivorous feeding habits
• social interactions
• winter denning
• aggressive behavior with other species and with
  other grizzlies
• mostly solitary-except for reproduction

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Ranges and Movement

• All these require large amounts of land
• Home ranges size may be 200,000 acres for males
  and 100,000 acres for females
• Concentrated food (for example, salmon runs) can
  allow limited co-existence for a short time

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Hibernation

• Find or excavate dens
• Enter den mid-October to mid-November emerge
  late March to early May
• Most individuals require at least 2 weeks to
  enter deep winter sleep

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Hibernation

• Unless disturbed, do not normally wake up until
  spring
• Body temperature does not decrease more than 5
  degrees C
• Do not usually feed, urinate or defecate during
  hibernation

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Estimated Population Size of Grizzly Bears in
North America. Location No. of
Bears ____________________________________________
___ NW Montana 400-500 Yellowstone
Ecosystem 400-600 Bitterroot Mts Selkirk
Mts. 40-50 Cabinet-Yaak (n.ID, nwMT) 30-40 No.
Cascades, WA 5? Subtotal (Continental
US) about 1100 Alaska 30,000 Canada

22,000 TOTAL 53,000
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Estimated Population Size of Grizzly Bears in
North America.
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Conservation

• Current status Threatened
• Date first listed July 28, 1975 (Current ESA)
• Experimental non-essential population proposal
  Selway-Bitteroot Mountains, Idaho and Montana

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Non-essential Experimental Population
Provision under the ESA that allows Threatened or
Endangered species to be introduced back into
previously occupied habitat. Animals engaged in
depredations or attacking humans can be destroyed
under this provision.
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Selway-Bitterroot Introduction

• Formation of a Citizen Management Committee
• Scientific Advisory Panel
• Results of public reaction to grizzly recovery
• 77 of 24,251 written comments favored recovery
• 61 favoring Citizen Management approach
• 60 of 294 residents that spoke at hearings
  favored

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Selway-Bitterroot Introduction

• Citizen Management Commitee
• 15 members, 6 year terms
• 7 Idaho citizens (1 a rep. of Idahos Fish Game
  Dept)
• 5 Montana citizens(1 a rep. of Montanas F, WL
  and Parks Dept)
• Nez Perce Tribe
• Fish Wildlife Service
• U.S. Forest Service

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Selway-Bitterroot Introduction

• Current Status
• Under Clinton administration, proposal made in
  2000 and USFW selected preferred alternative of
  reintroduction plan
• Under Bush administration, USFW re-evaluated
  decision and made preferred alternative the no
  action plan
• Recovery efforts to be focused on existing
  populations

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Conservation

• Factors that make conservation difficult
• 1. Potential danger to humans
• - some bears learn to look for garbage
• 2. Livestock depredations
• 3. Large amounts of land with little to no human
  activity needed

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Conservation
Aldo Leopolds land ethic A thing is right when
it tends to preserve the integrity, stability and
beauty of the biotic community.
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Conservation
Why restore Grizzlies? 1. Legally required
(ESA) 2. Biological reasons 3. Economic 4.
Spiritual/Ethical