WASHINGTON, D.C. -- Alaska's only U.S. representative has introduced legislation to delist polar bears as a threatened species.

Republican Don Young said in a prepared statement that listing an animal as threatened despite its increasing populations is absurd and "incredibly irresponsible."

Polar bears were listed in 2008 by Dirk Kempthorne, an Interior secretary under then-President George W. Bush, because of an alarming loss of summer sea ice in recent decades and climate models that indicate the trend will continue.

Polar bears use sea ice to hunt ringed seals and other prey.

Listing advocates say polar bear numbers rebounded after hunting restrictions were put in place but the greater threat is habitat loss. Four years ago, federal researchers reported that two-thirds of the world's polar bear habitat could vanish by mid-century.