Skull fossil found of the first human to migrate out of Africa

It must be a incredible treasure for scientists interested in human evolution. This research was funded in part by the National Geographic Society's Committee for Research and Exploration (CRE). The find calls into question a widely held hypothesis that the evolution of big brains propelled the exodus of early humans out of Africa. The fossil evidence from Dmanisi now includes three skulls, several jaw fragments, and hundreds of stone tools and animal remains. All of the material has been recovered from the same layer of sediment. It is forcing scientists to come up with alternative explanations for why humans were able to leave Africa.

"Before this find, the main reason was that at least these humans had big brains," said David Lordkipanidze, a paleoanthropologist at the Georgian State Museum in Tbilisi who led the excavation team. "Now this shows that [their brains] were quite small." The brain of the new specimen from Dmanisi is about half the size of a modern human's brain. The two skulls found in 1999 at the site are also about 1.8 million years old and had room for substantially larger brains.

The variation among the hominids recovered at Dmanisi makes it difficult to say exactly who these people were, said Lordkipanidze. He suggests that the variation may force scientists to rethink the definition of "Homo." "The Dmanisi fossils show much more variation than we would have expected from any group of humans at that time," said Ferring. Now scientists must ask the question: If not brain power and tool technology, what did enable early humans to leave Africa? Stein Morten Lund, 10 July 2002

Additional information • Read more on our website about discoveries of human skulls that rose new questions about evolutionary origin.

• The research by Lordkipanidze and colleagues is published in the 5 July 2002 issue of the journal Science and is the subject of the cover story of the August 2002 issue of National Geographic magazine.