Verbose
Deity
No way to know, except perhaps... "Chimp archaeology"!have they been doing this forever?

And yes, that already exists. Some biologists working in the Ivory Coast have found a place where chimps go to open their nuts (weeel...), that shows evidence of having been used for 4300 years.
http://primatology.org/2007/02/13/c...one-tools-made-by-chimps-from-4300-years-ago/