Transcript Grizzly (Brown) and Polar Bears - Wildlife Ecology and Conservation

By Christina Pilla
Grizzly
Kingdom: Animalia
Phylum: Chrodata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Genus: Ursus
Species: U. arctos
Polar
Kingdom: Animalia
Phylum: Chrodata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Genus: Ursus
Species: U. maritimus
•Found in the Late
Eocene to middle
Miocene
•Descendents of BearDogs
• Polar bears arose from
costal grizzlies
There are only 2 recognized extant subspecies of
brown bears in North America:
- U.a. horribilis
- U.a. middendorffi
U.a. Californicus
No extant subspecies
are recognized
Only one fossil
subspecies
U.m.tyrannus
Cultural
Native American
importance
Hunting
Aesthetics
Economic
Bear skin rugs
Ecotourism
Big game species
Hunting Season
Strict regulations
$85 Licenses fee
$25 a tag
$500 for a required
Guide
~$10,000-$21,000 per
hunt
Cultural
Highly respected in
native cultures
Inuit hunting
Aesthetic
Wildlife viewing
Economic
Local economy
benefits
Sexually dimorphic
Females = 125-350kg
Males = 150-525kg
Pelage can be a variety
of color depending on
their location
Shoulder hump and
dished face
Largest land carnivore
in N.America
Also Sexually
Dimorphic
Males = 400-600kg
Females = 150-250kg
Specialized for living in
the Arctic
Habitat Generalists
Found in:
Woodlands
Forests
Alpine meadows
Prairies
Home range:
Females: 130-780 sq.km
Males: 520 – 1300 sq.km
Circumpolar
Found on:
Arctic sea ice
Islands
Continental coastlines
Prefer sea ice with
leads and polynyas
Home range = 5060,000 sq. km
Migratory
Omnivorous
Varies by location, season and
year
Spring: winter-killed
animals, ants, grasses and
sedges, clover, and
dandelion,
Summer: thistle, fireweed,
mushrooms, and moths
Fall: Berries, whitebark and
limber pine nuts, insect
nests and starchy tubers and
roots
99.99% Coca cola
Almost exclusively
carnivores
Primary food source:
Ringed seals
Opportunistic
Influenced by :
Food resource
Habitat selection
Denning areas
Grizzly home ranges
overlap
Females have smaller
home ranges than
males
Aggressive behavior
Closely tied to sea ice
Activity is affected by
season
High in Summer
months
Low in the Winter
Females go inland during
the summer
Polygamous
Herding of estrous
females
Delayed implantation
Two month gestation
period
Low rates of reproduction
Only fertile ~1 month
Breed from mid-May to
July
Born around Jan.
March
Litter size: ~2
Life span: 30 years
–
Breed from March – May
Born around Nov.- Jan.
Litter size ~2
Life span: 15-18 years
• 1:1 sex ratio
• Newborn cubs are very
vulnerable
• Lactation lasts 1.5-2.5 years
• Remain with mothers for 2-3
years
• Interval between litters: 2-4
years
• Sexual dimorphism
•
•
Grizzlies: 1.8 times larger
Polar bears: 2-3 times larger
Carnivorean lethargy
Lasts 3-7 months
Only pregnant polar bears
participate
Do not:
Eat
Drink
Defecate
Urinate
Can be easily aroused
Give birth during this time
Solitary animals
Mother/cubs
Sub adult male groups
Grizzly bears are more
social than Polar bears
Larger/older bears kill
younger bears for food
Aggregate around food
source
No natural enemies
Humans
Intraspecific killing
Parasites
Worms
Fleas/ticks
Toxoplasma gondii
Diseases
Canine/swine hepatitis
Rabies
Tooth and aging problems
Exertional Myopathy
Intraspecific killing
Toxic chemicals
Biomagnification
Climate change
Loss of prey
Parasites
Trichinella
Tooth and aging
IUCN – Least Concern
CITES Appendix I and II
Endangered Species Act
Protected in the Continental U.S.
Game Species
Alaska only
IUCN – Vulnerable
CITIES Appendix II
Game species in the U.S. and Canada
Females and cubs protected
Yearlings in some places
Human- Grizzly interactions
Increased in Nat. Parks
Grizzly bear fatalities
17 people killed since 2000
Sport hunting allowed in Canada
Must have Inuit guide and dog team
No regulation in Alaska
Human- Polar bear interactions
Increased over the years
Most bears that are aggressive towards humans are
killed
Polar Bear Alert Program (PBAP)
Last polar bear mauling : 1983
Habitat must meet need for:
Food
Space
Travel corridors
Winter denning
Refugias
Must stop development
Roads negatively influence
bear populations
A lot is relatively
unknown
Some problems
include:
Industrial
development
Tourism
Toxic chemicals
GLOBAL WARMING
Successful relocation
depends on a variety of
factors
Should be relocated at least
100 Km away
Subadult females least likely
to return
In Polar bears: PBAT
controlled
Both are vulnerable to development and
continuous human expansion
Doesn’t look good for either species
Brown, D.E. 1985. The Grizzly in the Southwest: Documentary of an Extinction. University of
Oklahoma Press, Norman.
Stirling, I. 1988. Polar Bears. The University of Michigan Press, Ann Arbor.
Prestrud, P., and I. Sterling. 1994. The international Polar Bear Agreement and the current status
polar bear conservation. Aquatic Mammals : 20.3:113-124
"Inuit Hunting Polar Bear." Polar Bears International. N.p.. Web. 10 OCT 2013.
<http://www.polarbearsinternational.org/media/images/inuit-hunting-polar-bear>.
Van Daele, L.J. and V.G. Barnes Jr. 2010. Management of Brown Bear Hunting on Kodiak Island,
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Sweden. January 2010.
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<http://www.adfg.alaska.gov/index.cfm?adfg=huntlicense.prices>.
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<http://www.nrmsc.usgs.gov/science/igbst/2013mort>.
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<http://fwp.mt.gov/recreation/safety/wildlife/bears/profile.html>.
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belugas, Delphinapterus leucas, in Bering and chukchi seas. Canada Field-Naturalist 101:141-146
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habituation and whitebark pine seed crops. Journal of Wildlife Management 56:432-444