How the Fight for the Gray Wolf Was Won & Lost Listen Download Embed Share Share this on Facebook (Opens in a new window) Share this on Twitter (Opens in a new window) Share this via Email By the 1930s, the U.S. federal government had killed Yellowstone's gray wolves. About 60 years later, it tried to reverse that. ( mlorenzphotography / Getty ) Produced by Elaine Chen Produced by PRI and WNYC