I think the final step of evolution would be chimps waxing their body hair, shaving their faces and starting to play poker.
Maybe they could even fake their own moon-landing [img]/images/graemlins/wink.gif[/img]
Currently the smartest chimps are supposed to have the IQ of a 4 year old human child. The question is of course if all of the really smart chimps participated in such studies. Maybe some of them didn't like the idea to help those stupid humans with their ridiculous experiements.
In my opinion it is realistic to assume that the smartest chimp is smarter than the most stupid human on earth - which may actually qualify him to be the major of Liverpool or similar towns.