Gray wolves once roamed the United States from Maine to Oregon and down the spine of the Rocky Mountains. But for decades, they were hunted and killed, erasing them from much of the country. Today, wolves are mounting a comeback, but their recovery is far from certain. The federal government has sought to remove wolves in the Rockies from the endangered species list, which would open the door for states to kill hundreds of them. NRDC fights to ensure their survival.