A Polar Bears life By: Marissa Rooney

All information gotten from google.com and http://www.hsus.org/marine_mammals/a_closer_look_at_marine_mammals/polar_bears/

About them The polar bear or the sea/ice bear are the world's largest land predators. 

They can be found in the Arctic, the U.S. (Alaska), Canada, Russia, Denmark (Greenland), and Norway.  Each of these countries either banned hunting or established rules for how many polar bears could be hunted within its own boundaries. These rules help keep polar bear populations stable. Today, 25,000 to 40,000 polar bears roam the Arctic.

Around the age of four or five the female polar bear can start having babies. They usually only have two cubs and they have these babies in a cave they've dug in a large snow drift.  They stay there over winter and come out in spring with the babies.  

The babies are much smaller than human babies when they're born.  They are the size of a rat and weigh little more than a pound.  They can grow to full man size in a year if they have lots of food.

About them #2 Polar bears are among the largest

members of the bear family. Their white coat is actually composed of hollow hairs that reflect sunlight, producing a whitish/yellow camouflage in their Arctic habitat. Underneath the snowy coat is black skin, which helps them retain heat from sunlight.

Polar bears mate between April and May. Shortly after fertilization, the embryo ceases development and floats inside the mother's womb for a period of four or more months. This process, called delayed implantation, allows the mother to feed and build up enough body fat to survive eight months of hibernation. Cubs are born about every three years, generally in litters of two. At birth, the cubs weigh approximately one and a half pounds. Males can grow to weigh as much as 1,000 pounds and reach 11 feet in length.

Polar bears are carnivores, feeding primarily on Arctic ringed seals. Their partially webbed paws allow them to swim, at a pace of six miles per hour, for up to 60 miles without rest. They live and hunt on frozen ice floes during winter months, and survive on berries and stored fat (and on human garbage in certain areas) when the short summer thaw forces them onto land, rendering seals inaccessible.

Polar bears primarily eat seals. They often rest silently at a seal’s breathing hole in the ice, waiting for a seal in the water to surface. Once the seal comes up, the bear will spring and sink its jagged teeth into the seal’s head.

Sometimes the polar bear stalks its prey. It may see a seal lying near its breathing hole and slowly move toward it, then charge it, biting its head or grabbing it with its massive claws. A polar bear may also hunt by swimming beneath the ice.

What Polar Bears Face Growing Threats

The World Conservation Union's Polar Bear Specialist Group has stated that polar bear populations could drop more than 30 percent in the coming 45 years. Polar bears are classified as vulnerable on the IUCN Red List of threatened species. Both the United States and Canada have also classified the polar bear as requiring special protections. The HSUS believes all nonessential human exploitation of polar bears, such as capture for display or trophy hunting, should be prohibited.

Polar bears, top predators in their arctic habitat, face growing threats to their survival from habitat loss and degradation, specifically from: 

climate change and sea ice reduction environmental contaminants and chemical pollutants development hunting and capture for public display 

climate change and sea ice reduction

Climate Change and Sea Ice Reduction Polar bears are highly adapted to their Arctic habitat. Recent declines in their

numbers can be linked to the retreat of sea ice and its formation later in the year. The Arctic Climate Impact Assessment reported in 2004 that the covering of summer ice in the Arctic shrunk by 15 to 20 percent in the past 30 years, and the decline was expected to accelerate. Further predicted reductions of 10 to 50 percent of annual sea ice and 50 to 100 percent of summer sea ice in the next 50 to 100 years present a considerable threat. Ice is breaking up earlier in some areas and is predicted to do so in other areas, forcing bears ashore before they build up sufficient fat stores or forcing them to swim longer distances, which may exhaust them, leading to drowning. Not only is the Arctic warming forcing the bears to feed for a shorter time, but it is also decreasing their prey base. The consequences are thinner, stressed bears, decreased female reproductive rates, and lower juvenile survival rates.

Although a broad consensus has emerged that human activities are contributing to global warming, greenhouse gas emissions continue to increase in the United States and abroad. The United States has refused to sign the Kyoto Protocol, an international agreement intended to decrease the human production of greenhouse gases. Without the participation of the United States, the protocol is unlikely to meet its 2012 goal of reduced emissions of 5 percent of 1990 values in developed countries. Even if this goal is met, it is not stringent enough to preserve the polar bears' habitat.

Environmental Contaminantsand Development

Environmental Contaminants The Arctic is considered a "sink" for environmental contaminants. Mercury,

organochlorines such as PCBs and DDT, and other toxins are carried northward in rivers, ocean currents, and the wind. These toxins accumulate at higher levels along the food chain. Researchers have found extremely high amounts of chemical pollutants in polar bears, the top Arctic predator, putting the bears in danger of bone mineral density loss, hormonal imbalance, physiological damage, and compromised immune systems. Bone mineral density loss is especially devastating in female polar bears, which must mobilize large amounts of calcium and phosphate during pregnancy and nursing. As an additional blow, the harmful effects of pollutants can interact negatively with the nutritional stress caused by global warming.

Melting sea ice has resulted in the opening of the Arctic to tourism and mineral and energy development. As more people visit the Arctic, noise pollution and interactions with polar bears increase. Polar bears are harassed by photographers and tourists wanting to come closer. Yet when the bears are attracted to human camps by the smell of food, they may be perceived as a threat and killed.

Oil and gas exploration is a growing threat to polar bears as well. Companies are eager to exploit the mineral reserves in the Arctic, but it comes at a great cost to the environment.

Hunting

Because of their long lives and slow reproduction, polar bears rely on high adult survival rates to maintain their numbers. Over-hunting of adults can cause a catastrophic crash in population. Half of the 20 recognized populations of polar bears are currently threatened by potential over-hunting. The remainder may be over-hunted in the near future if hunting quotas are not reduced. Subsistence hunting is permitted in Canada, Greenland and Alaska, and sport hunting is permitted in Canada and recently Greenland. The World Conservation Union Red List of Threatened Species cites "a potential risk of over-harvest due to increased quotas, excessive quotas or no quotas in Canada and Greenland and poaching in Russia."   

Although the United States prohibits non-subsistence hunting of polar bears under the Marine Mammal Protection Act and trophy hunting is arguably illegal under the International Agreement on the Conservation of Polar Bears, U.S. hunters are permitted to import the trophies from sport hunted polar bears from six Canadian populations—Southern Beaufort Sea, Northern Beaufort Sea, Western Hudson Bay, Lancaster Sound, Viscount Melville Sound, and Norwegian Bay. Declining populations in some areas have spurred the U.S. Fish and Wildlife Service to review the sustainability of hunting in these areas. Unfortunately, polar bears continue to be killed and imported into the United States while the Fish and Wildlife Service considers whether to lift its approvals for any of the six targeted populations.

Protections

Although the threats polar bears face are grim, two recent protection measures are encouraging signs that the species may yet be saved: 

A United States law passed in 2006 to implement the U.S.-Russia bilateral agreement on polar bear conservation 

A proposal to list them as threatened under the Endangered Species Act The U.S.-Russia Bilateral Agreement In the United States, the Marine Mammal Protection Act was passed by Congress in 1972 to prevent

the harassment, injuring, or killing of marine mammals, including the polar bear.  In 1973, the devastation of polar bear populations from sport hunting prompted countries with polar bear populations—Canada, Denmark (on behalf of Greenland), Norway, the Soviet Union (now the Russian Federation), and the United States—to sign the International Agreement on the Conservation of Polar Bears. Along with provisions for habitat conservation and subsistence hunting, the agreement called for each country to develop a conservation program.

In October, 2000, the Russian Federation and the United States negotiated abilateral agreement on the Conservation and Management of the Alaska-Chukotka Polar Bear Population, which provided greater protections for the countries' shared population than found in the 1973 Agreement. The purpose of this bilateral agreement was to establish a joint management mechanism, particularly necessary to help curb poaching in Russia.  The U.S.-Russia Bilateral Agreement on Polar Bear Conservation

Polar bears are rapidly losing their habitat to rising temperatures, environmental contaminants, and development. Additionally, unsustainable hunting is threatening some populations. To save the species, conservation measures must quickly be developed and implemented; listing the polar bear under the ESA would be a step in this direction.

Protections includes provisions for setting hunt quotas. Quotas are not required under the Marine Mammal Protection Act, the only

restriction on subsistence hunts is that they must not be "wasteful"; prohibits the hunting of denning bears, females with cubs, and cubs under one year of age; does not allow the use of aircraft, large motorized vehicles, snares or poison for hunting purposes; allows for greater research opportunities; restricts commercial uses of harvested polar bears to handicrafts by Native people; and  created a Polar Bear Commission to consider scientific information on polar bears, set annual hunt quotas, and recommend

conservation measures.  On June 6, 2006, the Senate unanimously approved the 

United States-Russia Polar Bear Conservation and Management Implementation Act (S. 2013). This legislation amends the Marine Mammal Protection Act to allow the implementation of the bilateral agreement, and it specifies how two U.S. representatives—one from the federal government and one from the Alaska Native community—will be appointed to a Polar Bear Commission.  On July 17, 2006, the House of Representatives passed similar implementing legislation (H.R. 4075). The two (which have minor differences) will be reconciled in conference and then sent to President Bush for his signature.  Russia has already ratified the bilateral agreement and has a framework for its implementation. It has appointed its representative to the Commission.

The Endangered Species Act In February 2005, the threat of extinction due to global warming prompted the Center for Biological Diversity, Greenpeace,

and the Natural Resources Defense Council to file a petition in with the United States Fish and Wildlife Service (FWS) to list the polar bear as threatened under the Endangered Species Act. After conducting a status review, the FWS found the listing warranted in December 2006 and solicited public comments for any final action.

The Endangered Species Act describes an endangered species as one that "is in danger of extinction throughout all or a significant portion of its range." In order to be considered threatened; the polar bear must be "likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range." According to the IUCN Red List assessment, polar bear populations are predicted to decline by more than 30 percent within 45 years.

Listing the polar bear under the ESA would force the U.S. government to take steps to protect this beleaguered species. Regulatory agencies would be required to take into account how their decisions affect polar bears, resulting in stricter pollution laws. According to the ESA petition, significant reductions in greenhouse gas emissions are imperative to ensure the survival of the iconic polar bear.

Male polar bears may grow 10 feet tall and weigh over 1400 pounds.  Females reach seven feet and weigh 650 pounds.  In the wild polar bears live up to age 25.

Despite what we think, a polar bear's fur is not white.  Each hair is clear hollow tube.  Polar bears look white because each hollow hair reflects the light. On sunny days, it traps the sun's infrared heat and keeps the bear warm at 98 degrees F (when they're resting).

 Polar bear fur is oily and water repellent. The hairs don't mat when wet, allowing the polar bears to easily shake free of water and any ice that may form after swimming. Polar bears have been known to swim 100 miles (161 kilometers) at a stretch.

Polar bears are only found in the Arctic region and are highly dependant on the pack ice there since they spend much of their time hundreds of miles from land. The most important habitats for polar bears are the edges of pack ice, where currents and wind interact with the ice, forming a continually melting and refreezing matrix of ice patches. These are the areas of greatest seal abundance and accessibility.

Individual polar bears can travel thousands of miles per year following the seasonal advance and retreat of sea ice. Polar bears are distributed throughout the Arctic region in 19 subpopulations. Alaska, Canada, Russia, Greenland and Norway have polar bear populations. 

Behavior Polar bears are highly dependant on older stable pack ice in the arctic region, where they spend much of their

time on the ice hunting, mating, and denning. They are generally solitary as adults, except during breeding and cub rearing.

Unlike brown bears, non breeding polar bear females and males do not hibernate or den in the winter. Pregnant polar bears need to eat a lot in the summer and fall in order to build up sufficient fat reserves for surviving the denning period, during which time they give birth to one-pound cubs and then nurse them to about 20-30 pounds before emerging from the den in March or April.

Did You Know? At birth, polar bear cubs are 12 to 14 inches long and weigh around one pound. Reproduction

Mating Season: Late March through MayGestation: About 8 months with delayed implantationLitter size: 1-4 cubs; 2 cubs most commonFemale polar bears locate denning sites in October on thick stable pack ice or on land. The young are born from November through January while the mothers are hibernating. Cubs will remain with their mothers for at least 2 ½ years. Female polar bears can produce five litters in their lifetime, which is one of the lowest reproductive rates of any mammal.

Global Warming and Other Threats Polar bears could be extinct by 2050 as their habitat melts away due to global warming.  The loss of snow pack,

thinning and disappearing sea ice all reduce essential habitat. Loss of sea ice leads to higher energy requirements to locate prey and a shortage of food.