However, even in the seemingly pristine Arctic environment, polar bears are threatened by the spread of hormone-disrupting chemicals and global warming. This affects the polar ice edge ecosystem, the habitat of walrus, seals and penguins, as well as bears.
Global warming could already be having a negative impact on polar bears. In Canada's Hudson Bay (see map), numbers have been declining according to a study by Canadian Wildlife Services. Ice on the bay is melting an average of three weeks earlier than in the mid-1970s. This forces polar bears to retreat further inland before they have been able to replenish their reserves of fat by feeding on seal pups, which live on the ice.
The polar bears in the Hudson Bay are unique in the Arctic because they fast for six to eight months of hibernation and rely on winter hunting for survival. Longer ice-free periods during the artic summer leave polar bears stranded onshore for longer periods. The delay in freeze-up causes polar bears to lose critical fat reserves affecting reproduction and the ability of pregnant females to produce enough milk for their cubs. Scientists can already document a 15 percent drop in birth rates.
Threatened by Global Warming