| first fossil chimpanzee. | there are thousands of fossils of hominins, but no fossil chimpanzee has yet been reported. the chimpanzee (pan) is the closest living relative to humans. chimpanzee populations today are confined to wooded west and central africa, whereas most hominin fossil sites occur in the semi-arid east african rift valley. this situation has fuelled speculation regarding causes for the divergence of the human and chimpanzee lineages five to eight million years ago. some investigators have invoked a shift ... | 2005 | 16136135 |