Well, as they say, elk don't know how many legs a horse has, eh?
But, we are talking about a BF, after all. An animal we assume to be smarter than the average bear. No sure what quadrupeds were native to the vicinity, besides mule deer, but if we believe a BF can't tell the tread of a delicate cloven hoof and a fully loaded (and steel shod) horse, we might want to reevaluate our assessment of their capabilities. Apparently, they ain't none too bright.