Today Grizzly Bears Tours this week Toxic Garbage
Today: Grizzly Bears Tours this week “Toxic Garbage Island” movie W 4/21 at 5 pm in JES A 121 A
Ecological Interconnections
We are only one of millions of species on earth.
Grizzly Bears
Grizzly bears are big.
How are bears related to each other? Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 28
12, 000 years ago: the grizzly ancestor shortfaced bear Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 15
Short-faced vs grizzly bears Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 17 and 23
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? Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 78
… mostly eat The Digestive System
Different mouth and teeth structures can tell about an animal’s diet Fig 41. 18
Grizzly bear teeth
Different teeth and diets grizzly cat dog panda Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 54
Carnivores have a short digestive system Fig 41. 19 Herbivores have a long digestive system
Bears Both humans and grizzly bears are omnivores. Our digestive systems can tell us about our ancestors. Fig 41. 19 Humans
About 75% of their diet is plants
They also eat carrion.
Some grizzlies are excellent predators, but most eat carrion. Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 85
Grizzlies constant search for food can lead to conflicts with humans. 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
There is not much to eat in winter. . .
Bears from temperate climates sleep over the winter in a den. (not hibernation)
Grizzlies have an amazing ability to gain and lose weight. Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 62 and 63
Grizzly reproduction Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 59
Female Grizzly Bear reproductive cycle juveniles on own den w/ mother fall winter young born summer fertilization spring Females are not fertile when caring for offspring
Grizzly Bear Reproduction Spring Summer Birth year copulation delayed gestation implantation birth Juvenile year 1 Offspring with mom (lactation) Offspring den with mom (lactation) Juvenile year 2 Offspring with mom (lactation) Offspring den with mom (lactation) Adolescent Offspring with mom year Offspring on own Fall Winter (in den)
Grizzly cubs are born in the den and are very small (~1 lb) Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 58
Female Grizzly Bear reproductive cycle juveniles on own den w/ mother fall winter young born summer fertilization spring Females are not fertile when caring for offspring
Female bears are very protective of their young Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 76
Infanticide: males will try to kill young so that mother will become fertile Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 77
Habitat destruction and hunting have severely decreased grizzly populations in the U. S. Current Grizzly Bear range Historical Grizzly Bear range
Yellowstone NP 63 mi 54 mi • 466 mi of roads • 950 mi of backcountry trails • 97 trailheads • 287 backcountry campsites
Yellowstone Grizzly Bear population increases
Yellowstone NP is not big enough to support a viable grizzly bear population
Where do grizzly bears fit? Are they important? How much of our resources should we share with grizzly bears?
Animal behavior is unpredictable and inexplicable Bears (1993) Ian Stirling et al. , Weldon Owen Pty Ltd pg 231
Next: Ecology Introduction Tours this week “Toxic Garbage Island” movie W 4/21 at 5 pm in JES A 121 A
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