Steve Irwin, the enthusiastic, seemingly loopy Australian environmentalist and talk-show staple known as the Crocodile Hunter, died early this morning after being punctured in the chest by the barb of a stingray while filming an underwater documentary on the Great Barrier Reef in Queensland, north of Brisbane. He was 44. “He probably died from a cardiac arrest from the injury,” said a local diving operator after Irwin was pronounced dead at the scene. (Update)