Polar Bear: Arctic Icon at Risk

Polar Bear: Species Overview

Polar Bear Facts

Scientific Name: Ursus maritimus
Range: Arctic
Status: ”Threatened” under ESA
Cool fact 1: Polar bears are the world’s largest land carnivore.
Cool fact 2: Only pregnant female polar bears hibernate.
Global warming impacts: Fast disappearing Arctic sea ice is the polar bear’s feeding habitat.
Implications: As top-of-the-food-chain species, loss of polar bears could throw the Arctic out of ecological balance.

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The polar bear has become the iconic symbol of the threat of warming and rightly so – its survival is absolutely dependent on Arctic sea ice, which is rapidly disappearing.

Believed to have diverged from its cousin the brown bear around the time of the last ice age, polar bears are relative newcomers among bear species. Unlike their forebears, polar bears are full-time carnivores, depending almost entirely in seals to maintain their nearly 4 inch thick insulating layer of blubber.

An adult male can tilt the scales at 1500 lbs; females, half that.

Global Warming Threats

Bears hunt seals, their primary food source, at the edge of Arctic sea ice. As sea ice disappears, bear mortality rises. There are documented instances of bears drowning, unable to make the long swim from one ice flow to the next.

Polar bears also appear to be shrinking in size – researchers say the bears are a third smaller than they were 30 years ago as melting ice makes it harder for them to catch seals. Some are now even resorting to eating other bears to survive.

The World Conservation Union (IUCN) Red List has rated the polar bear as a "vulnerable species," defined as subject to a "high risk of extinction in the wild."

In 2008, the polar bear became the first animal to be added to the Endangered Species Act list of threatened species because of global warming.

An estimated 20,000 - 25,000 polar bears remain in the wild.

Wider Implications

The ice edge is the closest thing to a biological hotspot in the far North – many Arctic creatures make their homes there.

As polar bears are top predators, their disappearance could trigger a cascade of ecological consequences. Arctic foxes and gulls are among the species known to feed regularly on the remains of polar bear kills.

Bearded and ringed seals, polar bears' favorite foods, may also find survival difficult without the ice edge, presently the seals' breeding grounds.