Is a polar bear one of the eight species?
A polar bear is a one of the eight species. “Scientists believe that the polar bear began over 200,000 years ago. They came from the brown bears ancestors.”
As the ice caps are melting “the species most vulnerable , those at the edges of their natural ranges, would be affected first, which is what is happening now” (Bily 95). Many artic mammals rely on the sea’s biological productivity and on the presence of sea ice. One certain species that is dependent on the ice caps are Polar bears. Which in Cynthia Biles book, she states” Polar bears need sea ice as a platform from which to hunt their primary prey, to make seasonal migrations between the sea ice and their terrestrial denning areas” (
Polar bears are the largest of the bear species that live in the arctic region (Derocher & Stirling, 2012). Their habitat surrounds them with ice and water. Climate warming is an issue for all polar bears because they rely on sea ice to hunt for sea lions throughout the year to maintain energy (Derocher & Stirling, 2012). Polar bears hunt for sea lions to build up their energy for when sea lions aren’t available to them (Derocher & Stirling, 2012). If sea ice dissolves in the arctic area polar bears will start to disappear due to starvation. If predicted correctly, polar bears could stay in Northern Canadian arctic island and Northern Greenland but their population will decrease (Derocher & Stirling, 2012). Derocher and Sterling’s article about
Annual ice buildup in additional to a healthy seal population is vital for polar bears to mate and maintain a healthy population within the Hudson Bay. The rise in global temperature in the past decade has led to a decline of lone (likely pregnant) adult female polar bears in the Western Hudson Bay from 1980 to 2004 (see figures above) (Stirling and Parkinson, 274). The average female between 6- 18 years old has “an average litter size of 1.7, a sex ratio at birth of 1:1, and an average reproductive interval of 3.1 years” shows the average female can give birth up to 4 bears in their life time (DeMaster and Stirling, 3). The decrease in average monthly ice extends correlates with the mean body mass of lone female polar bears in the West Hudson Bay region. The earlier breaking-up of arctic ice likely shortened polar bear’s seal hunting time in Hudson Bay because less time to hunt directly affects the size and weight of female bears. Cubs are also likely to receive less nutrition from malnourished mothers and decrease survival rate. The hunting period before summer are responsible for nearly 70% or more of the energy bears needed to survive throughout the year. The early break up is causing adult polar bears, especially, females have less body mass. Data of sea ice breakup has shown that the “average date of break-up” is
Global warming is the increase in the average temperature of the Earth’s surface (Mastrandrea n. pag.). According to scientists, humans are the main cause of global warming. Scientists say global carbon dioxide emissions should be cut in half over the next fifty years or the effects may be irreversible (Eilperin n. pag.). The two main activities that humans do to contribute to global warming are burning fossil fuels and clearing land. Most of the fossil fuels come from burning in automobiles, factories and electric power plants which provide energy for houses and office buildings (McClure n. pag.). Continued global warming can cause harm to plants and animals that live in the sea and force plants and animals on land to move to new habitats. It could also change weather patterns that cause flooding, drought and an increase in damaging storms. Global warming could melt the polar ice caps enough to raise the sea level, and in certain parts of the world human disease could spread and crops being harvested could decline (Mastrandea n. pag.).
The major concern with GHG is the ability of GHG (like carbon dioxide, CO2) to absorb and trap heat while the pollutant is present in the atmosphere. It is believed by many the global temperature can be adversely affected if sufficient amounts of GHG emissions saturate the atmosphere. Most scientists agree the average temperature of the earth is rising. The earth has experienced many cycles of global warming and global cooling throughout its history. What is often debated is the amount of impact the pollutants from burning fossil fuels have on global warming. Most agree however, GHG should be regulated and reduced. One method touted as means for controlling GHG emissions is the cap-and-trade or carbon trading.
The tiny town of Churchill, situated on a peninsula jutting into the Western Hudson Bay in Manitoba, Canada, has become the window through which scientists and tourists watched the seemingly hopeless decline of the polar bear. For years, the melt of sea ice in the summer has driven polar bears off of their normal habitat and onto land, where they have wander the empty tundra surrounding Churchill and occasionally stroll past borders of the town itself. As global temperatures rise, sea ice covers Hudson Bay for an increasingly short time, leaving bears with a smaller window to hunt seals and a longer time onshore with little to eat. Yet the bears have an unlikely ally in the Churchill tundra: the snow goose.
In the wild, they prey primarily on the ringed seal but polar bears will also consume whales, walrus, reindeer, sea birds, and vegetation (Lintzenich et al., 2006). Their dietary intake is seasonally dependent. AZA Bear TAG (2009) explains that polar bears use the sea ice as their hunting grounds and when that ice melts, polar bears can be restricted to land for up to 6 months. During this time they may be forced to fast or have very limited food intake. Their survival during this time is dependent on the fat stores they were able to build prior to the warmer season (Dyck & Morrin, 2011). Polar bears live a very active lifestyle so the consumption of high energy food is important. The most important nutrients that need to be included in their diet are protein, fat, carbohydrates (plant material), vitamins (Vitamin A, Vitamin B, etc.), minerals (Iron, Zinc, Copper, etc.), and water (Lintzenich et al.,
Polar bears have thick fur, huge paws and some other features that will make them well prepared for life in the harsh environment. In fact, they need sea ice for survival. Climate change is causing bigger and bigger area’s of the summer sea ice to melt. Experts say that there is hot weather patterns continue the Arctic could have no summer sea ice by 2050.
The Arctic climate is covered with snow and ice. The temperatures are very cold. The Polar Bear’s coat has two layers of fur and a layer of blubber (thick fat) underneath. Polar Bears use their big front paws to paddle through the water and their oil coated fur helps keep them dry when they get out of the water. A Polar Bear spends months wandering across the frozen surface of the Arctic, looking for food. They eat walruses, birds, fish and seals. Sometimes a Polar Bear has to spend a lot of time in the water searching for food or swimming from place to place to find something to eat.