"The outsized, hump-shouldered bruins were hunted, trapped and poisoned to the edge of extinction in the lower 48 states before being added to the federal endangered and threatened species list in 1975.
The Center for Biological Diversity argued in a formal petition submitted to the U.S. Interior Department that grizzlies should be restored to their native range in such places as California's Sierra Nevada and the Grand Canyon in Arizona.
The areas, it said, still contain large tracts of undeveloped habitat favored by the bears.
'We've just begun the job of recovering grizzlies. There is so much more to do to see the bears restored to more of their range in the western United States,' said Noah Greenwald, endangered species director for the Center for Biological Diversity."