[Wyody]

Hard to figure the size, 53.
Well, my first thoughts are to figure out what animule we know it could be and figure out why one toe didn't leave a print.
I've been out west too long - can't recall if we even have sloths in this country. Seems like we do - can't recall if I've seen one or not.
Then, there's also the notion that it is a prehistoric print exposed by a glacier-melt ... don't remember too many glacier-fields near Sheridan ... but we have many strange animules from prehistoric Wyoming - like, for example, a duck-billed platypus found at 10,000 ft. near Kemmerer/Diamondville.
Off-hand, I'd say somebody somewhere picked up a hitchhiker or somebody else had a good time inventing a print in the mud.
You keep looking and I'll try and find a good recipe for Sloth-Stew. This might be a left-over from Ice Age 2!