Sasquatch, Yety, vilas, nymphs, elves and dwarves.....what if they actually were some lost tribes and communities we couldn't keep record of, but our ancestors have seen them and kept them in their folklore?
Neanderthals fit the bill and they have left traces of their existence. They lived in Europe until Homo Sapiens (us) arrived then went extinct shortly afterwards. There may well have been other such creatures that have found their way into our myths and legends. I wonder what they thought of us?