(Andy Barron | Reno Gazette-Journal | The Associated Press) In this Jan. 13, 2010 file photo, two young wild horses play while grazing in Reno, Nev. Animal rights activists are suing to block what they say is an unprecedented federal plan to capture thousands of wild horses over 10 years in Nevada without the legally required environmental reviews intended to protect the mustangs and U.S. rangeland.