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Putting Animal Physiology and Ecology together… Grizzly Bears
Ecological Interconnections
CB 54.2Interconnections
We are only one of millionsofspeciesonearth.
SpeciesintroductionsHunting
HabitatDestructionOther
39%
23%
36%
2%Why are species going extinct?
Nearly Extinct Species:maybe only 100 individuals exist
CB 55.3
Habitat loss and fragmentation has been extensive in the US due to human modification of the environment
What responsibility do we have for the well-being of non-humans?
Under what circumstance should we put the needs of non-humans above the needs of humans?
Grizzly Bears
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 28
How are bears related to each other?
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 15
12,000 years ago: the grizzly ancestor short-faced bear
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 17 and 23
Short-faced vs grizzly bears
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 28
How closely related are these bear species?
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 200
Grizzly-Polar bear hybrid (from a zoo)
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 78
Grizzly bears live most of their lives alone
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 78
Grizzly bears live most of their lives alone.
What do they do?
About 75% of their diet is plants
They also eat carrion.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 85
Some grizzlies are excellent predators, but most eat carrion.
Bears from temperate climates sleep over the winter in a den.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 62 and 63
Grizzlies have an amazing ability to gain and lose weight.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 186
Grizzlies constant search for food can lead to conflicts with humans.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 215
Grizzlies constant search for food can lead to conflicts with humans.
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 54
cat
dog
grizzly
panda
Different teeth and diets
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 59
Grizzly reproduction
Spring Summer Fall Winter
(in den)
Birth
year
copulation delayed implantation
gestation birth
Juvenile
year 1
Offspring with mom
(lactation)
Offspring with mom
(lactation)
Offspring with mom
(lactation)
Offspring den with mom
(lactation)
Juvenile
year 2
Offspring with mom
(lactation)
Offspring with mom
(lactation)
Offspring with mom
(lactation)
Offspring den with mom
(lactation)
Adolescent
year
Offspring with mom
(lactation)
Offspring on own
Grizzly Bear Reproduction
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 58
Grizzly cubs are born in the den and are very small (~1 lb)
winter
fall
summer
spring
youngborn
den w/motherjuveniles
on own
Female Grizzly Bear reproductive cycle
Females are not fertile when caring for offspring
fertiliz-ation
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 76
Female bears are very protective of their young
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 77
Infanticide: males will try to kill young so that mother will become fertile
Human-Bear Interactions
Historical Grizzly Bear range
Current Grizzly Bear range
Hunting Grizzlies
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 216
Hunters
Studying Grizzlies
CB55.11
63 mi
54 mi
•466 mi of roads •950 mi of backcountry trails•97 trailheads•287 backcountry campsites
Yellowstone NP
CB 55.12
Yellowstone Grizzly Bear population increases
CB 55.16
Artificial corridors allow animals to cross fragmented areas
CB 55.16
CB 55.18
Where do grizzly bears fit?
Are they important?
How much of our resources should we share with grizzly bears?
Bears (1993) Ian Stirling et al., Weldon Owen Pty Ltd pg 231
Animal behavior is unpredictable and inexplicable
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