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Evolution of polar bears
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Recommended: Evolution of polar bears
Polar Bear Evolution is a Continuing Story
The polar bear, the largest land carnivore in North America, one of the largest animals in the world and a favorite at zoos worldwide, has, over the years, adapted to its harsh Arctic environment. The appropriately named ‘ursus maritimum’ or sea bear usually lives between 15 and 18 years in the wild and spends most of its life on ice. It is the most recent of the eight bear species. The first polar bear was a brown bear subspecies, with brown bear dimensions and brown bear teeth. The polar bear evolution was rapid due to the small population and extreme pressure to survive. Even today, the polar bear continues to evolve to better adapt to the harsh realities of Arctic life.
Today’s polar bear evolved from the brown bear. The polar bear can reach weights of more than 1000 pounds. They can swim 100 miles without a break. Their body is longer than an ordinary brown bear and they lack a shoulder hump. Evolution has worked well for the polar bear in its efforts to survive a barren and cold life.
In the overall history of evolution, polar bears are a fairly young breed. Over 200,000 years ago, glaciers covered much of the earth. Hungry brown bears, probably isolated in the glaciers near Siberia and looking for something to eat, discovered seals. The first bears probably just ate seal carcasses that washed ashore because that was their hunting capability at the time. Within 75,000 years (a short period in evolutionary time), rapid changes took place so bears could survive on ice, be an aggressive hunter and reproduce in a frigid land. That new species, the early polar bear, arrived during the mid-Pleistocene period. The early polar bear was much larger than today’s polar bear (Evolution of ...
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...lution was and will continue to be the main element of polar bear adaptability for the future.
Works Cited
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Eliot, John. L. “Polar Bears: Stalkers of the High Artic.” National Geographic 193.1 (Jan. 1998): 52-71.
“Evolution of Polar Bears.” University of Maryland, Department of Geology Site. 17 April 2003
“Field Guide: Polar Bear.” Canadian Wildlife 8.4 (Fall 2002): 10.
Milius, Susan. “Giants of the North.” International Wildlife 24.5 (Sep-Oct 1994): 30-35.
Milner, Richard. “Sea Bear.” Natural History 110.1 (Feb. 2001): 84-85.
“Polar Bear Evolution.” Polar Bears Alive Site. 1995. 17 April 2003
Sherwonit, Bill. “The Bears of Alaska.” Wilderness (Winter 1999): 12-19.
Nature, it is everywhere, everyone uses it. Quite often, however, people abuse it, such as with humans’ impact on grizzly bears. Grizzly bears are important to the environment because they have many useful purposes for the environment: “they provide an “umbrella” for the environment because they require such large home ranges.” (savethegreatbear.org/CAD/Grizzly.htm) The Grizzly Bear is extremely vulnerable to changes in its habitat and food cycle. This allows humans to detect small changes in the environment, just by watching this amazing species. The Government of Canada needs to try harder to stop the poaching of grizzly bears in Canada.
The one way to keep bears and humans safe and living in the same environment is learning to understand them and being able to tolerate them. If people don’t do these things theses beautiful animals will begin to decrease in numbers. While there are a lot of black bears in Alaska, an estimated 100,000, hunters believe that you can just hunt and hunt and the population will decrease to average, but the plans of some hunters seems just over the top of making these bears go on to the endangered species list. But with the help of people and cooperation the Black Bears will continue to live in Alaska.
Bears can live anywhere but Grizzly bears live in subalpine meadows and dense forests. When grizzly bears hibernate they usually live in caves. A sloth of bears is usually a mom and the cubs. The mom bear is called a sow, the dad bear doesn't have a name because they are never with the family and the babies are called cubs. There is usually a dearth amount of cubs in a family. The families are always together and not with a different family. All bear look different but I'm not talking about the other bears I am talking about grizzly bears. Grizzly bears are usually just the color brown and not really anything different. Grizzlys need big paws to get around and travel. Bears have small black eyes. Their eyes are small because they don't need very good eyesight because they have such good sniffers. Usually the weight of a cub is about 4- 10 pounds when they are born but when they are adults they weigh 175- 500 pounds.
The Arctic region is home to a variety of valuable animals and plants, including polar bear, seal, and so on. The ecosystem of the Arctic region is fragile because these animals are evolved to live in extreme conditions. With the climate change, many animals are endangered. Ice is the habitat of polar animals because they have to rely on sea ices for resting, food, and reproduction. With the climate change and the decrease of sea ice, the number of polar animals is decreasing and their health is threatened. For example, the average weight of female polar bears in 1980 was about 650 pounds, but the number reduced to about 500 pounds in 2004 (Djoghlaf 15). The earlier breakup and later condensation of sea ice shortens the hunting season of polar bears. Polar bears mainly feed on seals that indwell icy land. The melting ice reduces the number of seals and food intake of polar bears. In addition, polar bears are used to living in ice caves. The rising temperature causes the collapse of ice caves, which can kill baby bears. The climate change is negatively affecting the biodiversity in the region and will definitely harm the ecosystem
Many people who hunt the limited Grizzly Bears do it to satisfy their own “needs” of achievements. The Grizzly bear is an exclusive species that is only local to British Columbia; therefore it adds to the feeling of achievement for hunters, but it also encourages individuals, environmental organizations, and the first nations to preserve this rare species. Hunting bears is not sustainable and it’s much worth it to have them alive to promote more advantageous benefits than to have them dead with their heads on the wall to amuse people or to disturb people’s thoughts of what was once a beautiful
Noceker, Robert J. ìCongressional Research Service Report for Congress Reintroduction of Wolves.î August 1, 1997. Visited: October 17, 1999.
The characteristics of the grizzly bear as a top predator also make it highly vulnerable to threats. Although it is an omnivore, because it relies heavily on salmon to make it through the winter, it is vulnerable to anything that impacts on salmon runs. It needs wide-ranging habitat and is slow to reproduce. As such, grizzly bears are considered not just a key species but also an ‘umbrella species’ because the protection of their habitats will result in an ‘umbrella of protection’ for a wide range of other species. The protected areas that have been set aside in the Great Bear Rainforest are not enough to sustain healthy populations of grizzly bear so it requires additional habitat set aside from logging. Trophy hunting of grizzly bears also continues to place their population at
Phillips, Michael K., Smith, Douglas W. The Wolves of Yellowstone. Voyage Press, Inc. 1996, pgs 25-30.
Ness, Erik, and Geoff Kern. Oh, the Deer. Discover Magazine Mar. 2003: n. pag. ii. p. ii
Out of an Ice Age emerged one of our most majestic creatures in the world the polar bear. From its brown bear ancestry, the predator evolved to be a master of a harsh and unwelcoming ice kingdom. Intelligent, adaptable and fierce, the polar bear learned how to survive in a place that offers few comforts to any creature. But now that very environment is in flux. And so is the polar bear’s fate (Nature). Polar Bears are very different from other bears. Polar bears are very large bears compared to Black bears. Polar bears weigh anywhere between 330-1700lbs and Black bears weigh anywhere between 150-600lbs. They have strong legs with large, flattened feet with some webbing between their toes that help with walking on ice and swimming. The wide paws prevent sea ice from breaking by distributing weight while walking. Their paws allow them to pull a 600 pound seal out of its breathing hole (Rosing, 20). The webbed feet results in making polar bears, unlike other bear species to be considered as marine mammals along with seals, sea lions, walruses, whales and dolphins (Polar Bear). According to Rosing Polar bears are excellent swimmers and have been known to swim up to six miles an hour and as far as 60 miles at a stretch. The bears paddle with their front feet and steer with their back feet. They often overheat. Sometimes they venture into the waters just to cool off. When a bear climbs on an ice floe, it shakes itself off because it is trying to prevent ice from forming on its fur (22-23). Because of climate change and hunting of polar bears are now becoming an endangered species which is affecting the food chain. We can fix this by going green, banning polar bear hunting and keep creating these new hybrid bears that are mixed with griz...
animals such as the polar bear, to mate and to prepare for the once again
Grizzly bears live in a variety of environments .All of which includes dense forests, subalpine meadows, open plains and arctic tundra . In the past though, they could be found from Alaska to Mexico, and from California to Ohio. Though Nowadays there are efforts trying to make it so grizzly bears can make a comeback and the wild, and all of their efforts are proving to be working, there are 4 times as many grizzlies in the wild as there were in 1975, at
According to the Alaska Department of Fish and Game, the brown bear is located all throughout Alaska, mostly in areas that allow them to seasonally hunt salmon (Alaska Fish & Game, 2010). This allows them to become larger and live in higher concentrations than the grizzly bear. The traditional brown bear and the grizzly bear are actually both classified as brown bears, despite having several differences in appearance. Brown bears are one of the most fascinating and powerful species in the Alaskan wilderness. Cubs are usually born during January or February, usually in groups of one to four (Alaska Fish & Game). A fully grown, male brown bear can weigh up for 1,500 pounds and be over 10 feet in stature (Alaska Fish & Game, 2010). Brown bears also have the ability to run at speeds up to 40 mph for short bursts of time (Alaska Fish & Game). All of these unique characteristics make many people upset that it is legal to hunt them. There are several groups that are working to conserve the brown bear population, particularly in Alaska, such as The Northern Forum’s Brown Bear Working Group (Fish & Wildlife Journal, 2010). The bear population in Alaska is thriving and is classified as a status of least concern, by the IUCN Red List (IUCN, 2010). Overall, the brown bear population faces no danger whatsoever.
To begin with, the melting of polar ice caps has caused polar bears to swim long distances. According to Bryan Walsh of TIME Magazine the melting of the ice caps have caused polar bears especially the young cubs to swim longer distances which has caused a “ forty-five percent mortality rate” (Walsh). In the article Walsh, writes about a study that showed that younger cubs because of low fat and strength were more likely to die due to the long di...
Bears begin to reach sexual maturity at different times. “Females generally become sexually mature between two to five years of age. Males become sexually mature at four to six years of age. “ (Callas, 2002) Mating seasons are between June and July, with th...