A friend of my wife's has a horse farm up in Virginia and she emailed us what she thought were bear tracks going through the mud on the way to one of her barns. After studying the pics, they are no doubt mountain lion tracks. Even though she lives in a fairly remote area (outside of Floyd, Va.), I suspect the tracks belong to a cougar that was probably captive bred & released or escaped. They are very adaptable animals and exploit their environment extremely well. Between rabbits, squirrels, raccoons, opossums, deer, quail, turkeys, barnyard animals, livestock, & pets, there's a lot of food for a big cat to prey upon.
Given that her horses have not been attacked and the tracks have not been seen around there since, I imagine that cat was just passing through. It freaked her out in a big way. You can bet her horses stay locked up at night.