Earthjustice, an environmental law firm, filed a lawsuit last week aimed at forcing the federal government to protect wolverines under the Endangered Species Act. The elusive and far-ranging animal has failed to gain status because there is so little known about them, the reason cited by Fish and Wildlife Service in 2003. Ironically, because they are so few in number, studies to determine actual numbers have been difficult. But recent studies by private and government research groups may show new population density figures that evironmentalists hope will allow them to attain status and eliminate trapping and hunting seasons in Western states. Once found in most Northern states, wolverines now have been found only in Idaho, Montana, Wyoming and Washington with infrequent sighting reports from Oregon and California.