Putting Animal Physiology and Ecology together… Grizzly Bears

Ecological Interconnections

CB 54.2 Interconnections

We are only one of millions of species on earth.

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

SpringSummerFallWinter (in den) Birth year copulationdelayed implantation gestationbirth 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 young born den w/ mother juveniles 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 CB 55.11

63 mi 54 mi 466 mi of roads 950 mi of backcountry trails 97 trailheads 287 backcountry campsites Yellowstone NP

CB Yellowstone Grizzly Bear population increases

CB Artificial corridors allow animals to cross fragmented areas CB 55.16

CB 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