DALLAS — A permit to hunt an endangered African black rhino sold for $350,000 at a Dallas auction held to raise money for conservation efforts but criticized by wildlife advocates. Steve Wagner, a spokesman for the Dallas Safari Club, which sponsored the closed-door event Saturday night, confirmed the sale of the permit for a hunt in the African nation of Namibia. He declined to name the buyer. The Safari Club's executive director, Ben Carter, has defended the auction, saying all money raised will go toward protecting the species. He also said the rhino that the winner will be allowed to hunt is old, male and nonbreeding — and that the animal was likely to be targeted for removal anyway because it was becoming aggressive and threatening other wildlife. But the auction drew howls from critics, including wildlife and animal rights groups, and the FBI said it was investigating death threats against members of the club. Officials from the Humane Society and the International Fund for Animal Welfare have said that while culling can be appropriate in abundant animal populations, all black rhinos should be protected, given their endangered status. An estimated 4,000 black rhinos remain in the wild, down from 70,000 in the 1960s. Nearly 1,800 are in Namibia, according to the Safari Club. Critics have also said any hunting of a rhino sends a bad message to the public. — AP