A couple went riding and found tem selves being
stalked by a mountain lion. The husband dismounted
wit his rifle and the wife with her camera. The mule
decided he didn't like the situation and took charge.
This is an old hoax . The mule did not kill the mountain lion, nor was the "couple" stalked. This mule however was still very unusual, in that it liked to nuzzle the dead lions, after they were shot. It got to the point, that the mule would actually pick them up---hence this picture.
Source: truthorfiction.com, circa 2002-3