My family has stories of "black panthers" in post civil war Arkansas & region, yet as said, not one documented pelt, photo or dead mountain lion ever turns out to be black. OTOH I have seen a black one: it came to a call on an overcast day in the snow. I'm sure that had I killed it, it would have turned out to be in the normal range of cougar colorations, some of which are quite dark reds or greys. It looked jet black in that light condition.
I have seen several mt. lions in the wild, and the single most noticeable characteristic IME is the tail: big and waving or flowing or doing something. Fabulous animal to see.
