Stock Photo - Mother polar bear Ursus maritimus with two coy cubs_of_year on multi_year ice floes in the Barents Sea off the eastern side of Heleysundet in the Svalbard Archipelago, Norway An adult male weighs around 400680 kg 8801,500 lb while an adult female is about half that size The IUCN now lists global warming as the most significant threat to the polar bear, primarily because the melting of its sea ice habitat reduces its ability to find sufficient food The IUCN states, ´If climatic trends continue polar bears may become extirpated from most of their range within 100 years ´ On May 14, 2008, the United States Department of the Interior listed the polar bear as a threatened species under the Endangered Species Act