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First Humans to Leave Africa Weren't Necessarily a Brainy Bunch




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A longstanding view of human evolution holds that the first hominids to leave Africa did so with the help of bigger brains, longer legs and fancier tools than those of their predecessors. That scenario suffered a major blow a couple of years ago, however, when paleontologists working in Dmanisi, Georgia unearthed the oldest human remains yet found outside of Africa---two 1.7-million-year-old skulls belonging to early members of our genus, Homo--and discovered primitive tools alongside them. Now a new finding may topple another pillar of the theory. According to a report in the current issue of the journal Science, researchers working at the same site have recovered a third skull--one that housed a surprisingly small brain.

Exceptionally well-preserved, the fossil, dubbed D2700, exhibits a thin browridge, short nose and large canine teeth, observes team member David Lordkipanidze of the Georgian Academy of Sciences in Tbilisi. With an endocranial volume of roughly 600 cubic centimeters, D2700 was considerably smaller-brained than the other two Dmanisi hominids, whose skulls have some 800 cubic centimeters of brain space. But size differences notwithstanding, the three specimens are, overall, similar in form. The investigators thus believe that the remains represent members of the same species, H. erectus, although they have some features characteristic of the more primitive Homo habilis. It may well be that the D2700 individual was a female and the other two were males, the team posits.

Only time and more fossils will reveal who these intrepid travelers were and why they left their motherland. But as is so often the case in paleoanthropology, the emerging picture appears to be far more complex than previously thought.

"We Were Not Alone," by Ian Tattersall (Scientific American, January 2000), is available for purchase at the Scientific American Archive.
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