Defenders' Experts
Polar Bear Background and Recovery
Description
Polar bears are among the largest carnivores in the world, rivaled only by the Kodiak brown bears of southern Alaska. As its scientific name, Ursusmaritimus, suggests, the polar bear is primarily a marine bear.
Numerous adaptations uniquely suit them to life in icy habitats. Their fur is thicker than any other bears’ and covers even their feet, for warmth and traction on ice.
Polar bears can swim as far as 40 miles. The long neck and narrow skull of the polar bear probably aid in streamlining the animal in the water,and the front feet are large, flat and oarlike. A thick layer of blubber provides buoyancy and insulation.
Polar Bear Habitat and Diet
Highly dependent on pack ice in the arctic region, polar bears spend much of their time hundreds of miles from land. Polar bears travel great distances in search of prey, which consists mainly of ringed seals and bearded seals.
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 bears can travel thousands of miles per year following the seasonal advance and retreat of sea ice.
In one study, a single radio-collared animal ranged over an area encompassing most of the north coast of Alaska—nearly 200,000 square miles. Polar bears can also swim as far as 40 miles.
Polar Bear Population in Decline
The World Conservation Union (IUCN) estimates that there are between 20,000 and 25,000 polar bears in the world, distributed throughout the Arctic region in 19 subpopulations. Many of these are difficult to track accurately, but most signs indicate the total number of polar bears in the world is at or below 20,000 and diminishing.
Only two of the world’s 19 polar bear subpopulations – Chukchi Sea and Southern Beaufort Sea – are found in Alaska, the only place in the U.S. they occur. Sadly, both of these populations are in decline. Climate change has had such a dramatic impact on polar bear populations that our children could be the last generation to see polar bears on U.S. shores.
Threats to Polar Bears
Climate Change: The most serious threat to polar bears today is climate change. As temperatures in the Arctic continue to get warmer, the sea ice that polar bears rely on for survival melts at an alarming and accelerating rate.
Sea Bear Under Siege:
Polar Bears and Climate Change in Alaska
This report details the threats climate change poses to the polar bear and offers an extensive list of actions that should be undertaken to assist these Arctic marine animals.
Oil Exploration: Most experts agree that the greatest direct risk to polar bears from oil and gas development is major oil spills, because there is still no proven method of cleaning up oil in broken sea-ice conditions. Oil spills would not only directly harm polar bears, but would also deplete their prey and contaminate their habitat.
Learn more about how offshore drilling can impact the polar bear’s Arctic environment.
Pollution: Prevailing winds and water currents deposit residues of PCBs, pesticides and other persistent toxins in the Arctic region. Pollutants are stored in the animals’ fat and accumulate, so top predators such as polar bears receive doses sufficient to interfere with reproduction, growth and development, and immune function.
Tourism: Although ecotourism and sightseeing focused on polar bears are growing, current oversight of these operations is minimal. To keep bears and people safe, it will become increasingly important to enforce regulations on observation distances and harassment.
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