The Grizzly Bear (Ursus arctos horribilis)
By Maxwell Thompson
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Description and Ecology
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The Grizzly Bear is at the top of its trophic level and a K selected species. The omnivorous mammal primarily feeds on berries, fruits, and leaves. However, they do eat other animals, from mice, salmon, deer, and moose.
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Geographic and Population Changes
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Grizzly populations once occupied all of western North America and extended as far out to the Great Plains. States the Grizzly bear once occupied in the United States include California, Oregon, Arizona, Colorado, Idaho, Montana, Nevada, Wyoming, New Mexico, Utah, and Washington state. Populations once ranged all the way from Mexico to Alaska. Today, the only occupy the the far western side of Canada and Alaska. They also are Grizzlies in Yosemite National Park, and this is because the strict laws that have protected Grizzlies over the years.
Human settlement is 100% the main factor that has caused bear populations to diminish drastically. Between 1850 and 1970, approximately 98% of the grizzly population was eliminated before 1850 there use to be around 50,000 Grizzlies. It 1975, there was approximately 800-1000 bears left. Grizzlies received an endangered species act in 1975, and have shown great recovery since. In Yosemite in 1975, the population was 136. Today, it is over 690 bears.
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Human settlement is 100% the main factor that has caused bear populations to diminish drastically. Between 1850 and 1970, approximately 98% of the grizzly population was eliminated before 1850 there use to be around 50,000 Grizzlies. It 1975, there was approximately 800-1000 bears left. Grizzlies received an endangered species act in 1975, and have shown great recovery since. In Yosemite in 1975, the population was 136. Today, it is over 690 bears.
Types of Listing and Listing Dates
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Threats to Existence
There are three factors that have caused the Grizzly population to diminish so drastically, and they all relate to human settlement. The first reason is habitat degradation: logging, the construction of roads, and oil drilling have all forced Grizzlies out of their habitat. All of these not only force Grizzlies out the area, but strand individuals in habitats that cannot support themselves. The entire are they roamed has been fragmented, and as a result bears will not cross barriers to reach other segmented areas. These barriers are physical like roads, but are also mental. Grizzlies will not want to enter a new area if there is a clear opening, making it a physiological barrier to the bears.
Second is hunting by humans. European exploration in the 1800's have hunted these bears to the point where they are endangered today. They were considered a big game because of their size and ferocity.
Third and that is still an issue today, is Global Warming. Global warming has reduced the amount of time bears will hibernate. When bears hibernate, they reduce the amount of energy they spend by 85%. When bears are done hibernating, this a time when the females give birth and raise their children. With not having the energy due to hibernation, raising young and going long months without food become a problem. In addition, with global warming comes a diminishing salmon population. this is a critical protein based food source for the Grizzly bear. As the salmon population diminishes, the Bear's will need to find other sources of food to compensate.
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Second is hunting by humans. European exploration in the 1800's have hunted these bears to the point where they are endangered today. They were considered a big game because of their size and ferocity.
Third and that is still an issue today, is Global Warming. Global warming has reduced the amount of time bears will hibernate. When bears hibernate, they reduce the amount of energy they spend by 85%. When bears are done hibernating, this a time when the females give birth and raise their children. With not having the energy due to hibernation, raising young and going long months without food become a problem. In addition, with global warming comes a diminishing salmon population. this is a critical protein based food source for the Grizzly bear. As the salmon population diminishes, the Bear's will need to find other sources of food to compensate.
What Can We Do?
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Unfortunately, when bears make a mistake, the whole species take a downfall. When a bear kills a person, that bear will often be hunted and the whole bear group receives a bad name. Bears are not looking for trouble with humans; but with that said, they are defiantly an animal you must never underestimate.When going into Grizzly country, or any bear country really, bring bear spray instead of a gun: give the bear a chance to run away temporarily harmed versus dead. Again, bears are curious animals. It can be very intimidating just seeing a bear in the wild (trust me, I know).
Also, Grizzly bears entering human settlements are a huge reason for bear mortalities. Installing Electrical fences around farm property, trash, and homes will prevent bears from entering and inspecting the areas. Here is a website were you can donate money to create bear safe electrical fences http://www.defenders.org/help-us-protect-grizzly-bears. This website has saved the lives of many grizzlies and even black bears from death.
Thank you for reading!
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Other Resources
(National Geographic) https://www.nationalgeographic.com/animals/mammals/g/grizzly-bear/
(Yellowstone) https://www.nps.gov/yell/learn/nature/bearesa.htm
(Center for Biological Diversity) http://www.biologicaldiversity.org/species/mammals/grizzly_bear/natural_history.html
Bibliography
(Center for Biological Diversity) http://www.biologicaldiversity.org/species/mammals/grizzly_bear/natural_history.html
Bibliography
(Ecosystem) http://skyschool.arizona.edu/wp-content/uploads/2013/02/The-Habitable-Planet-Ecosystems-1-Hough.pdf
(Ecos) https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=A001
(Raincoast) https://www.raincoast.org/projects/grizzly-bears/habitat/
Grizzly bears are such beautiful animals, I really enjoyed your blog. It is really sad that bears are looked at in such negative scrutiny, but it is amazing that they went from a small population of 136 to almost 700 bears today!
ReplyDelete-Daniel Tomer
DeleteThe graphic of the grizzly bear anatomy was very useful! I had no idea that bears had such long lifespans. The growth the population has seen is truly reassuring, hopefully bears will stop being targeted in mass for the interactions of a single bear and a single person. -Sophie Topping Zimmerman
ReplyDeleteHey! This was great! My project was on polar bears, so the bears are something that are very close to me. I think it is so interesting the resemblance the two have. Such as both are really struggling with habitat destruction. - Grantland T
ReplyDeleteGreat blog! It's so sad that these creatures are purposely hunted and seen negatively in our society. I thought it was interesting reading about how global warming has impacted the bears; I think this is something that people oftentimes forget about. -Alyssa Slattery
ReplyDelete