Due to the lack of fossil evidences in Africa, it is a common belief among experts that the common ancestors of great apes and humans left the region for Europe and Asia around seven to 13 million years ago. The ancient apes then migrated to other continents before eventually going back to Africa.

A recent finding, however, suggests otherwise. A 10-million year old jawbone of a great ape has just been found in the Nakali region of Kenya. The fossil was found by researchers headed by Yutaka Kunimatsu of Kyoto University's Primate Research Institute.

The team believe that the jawbone belongs to an entirely new species of the great ape. They added that they have a good reason to believe that this species holds the key to the genetic split of great apes and Homo Sapiens. Kunimatsu explained:

It could be positioned before the split between gorillas, chimps, and humans. We only have some jaw fragments and some teeth but we hope to find other body parts in our future research. We plan to go back next year. We will try to find bones below the neck to tell us how the animal moved.

Now, we have a good candidate in Africa. We do not need to think the common ancestor came back from Eurasia to Africa. I think it is more likely the common ancestor evolved from the apes in the Miocene in Africa. Some apes left Africa and migrated to Eurasia.

They then became orangutans in Southeast Asia. Today's orangutan evolved from the apes that left Africa.