Chimps are not ancestral to humans. Our common ancestor was hairy and swung in the trees, but they were not chimps. They were chimp-like, and they were human-like, but these apes (proconsul) gave rise to all the great apes and hominids, and its only the extinction of all the other hominids that allows us to exclude great apes from the hominids. In short, humans are basically chimps, and chimps (and other non-human primates) are basically humans. But humans are basically shrews, basically lizards, basically fish, depending on how basic you want to get. If we can bring ourselves to see humans as one animal amongst many, the skeletons speak for themselves.
Human Evolution in 42 Steps
™ Version 4.2