Big game hunter Corey Knowlton’s long wait to kill an endangered black rhinoceros in Africa is finally over. In a decision Thursday that’s certain to rile animal rights activists, the U.S. Fish and Wildlife Service removed the last hurdle in the way of Knowlton’s quest. More than a year after the wealthy Texan submitted the winning $350,000 bid for a Namibian government permit at a Dallas auction to shoot the animal, the agency announced that it approved his application for a separate U.S.