Palin said last week that listing the bears as threatened under the federal Endangered Species Act because of possible global warming would open the floodgates for petitions to protect other species, the Anchorage Daily News said Thursday.

New studies by the U.S. Geological Survey predict two-thirds of the world's polar bears could be gone in 50 years because of the shrinking summer ice cap. The newspaper said a federal decision whether to list polar bears as threatened is expected by January.