Out of Africa

More than 2 million years ago, our ancestors were already world travelers, trekking all the way from Africa to Asia, according to stone tools found on a cliff face in north-central China. The age of the tools suggests that the forebears of modern humans left Africa at least 250,000 years earlier than thought; it also supports a minority view that a key human ancestor, Homo erectus, may have originated in Asia, not in Africa.

Until now, the oldest evidence of human ancestors outside of Africa was in Dmanisi, Georgia. Here, fossils of short people thought to be early H. erectus date back to about 1.85 million years—just after the species appears in Africa. The oldest evidence of early human activity in China and Indonesia has been fossils and stone tools that date to 1.5 million to 1.7 million years ago, including a skullcap of H. erectus from a site just 4 kilometers south of the newly dated tools. This trail of stones and bones has suggested that after the earliest members of our own genus Homo appeared about 2.8 million years ago in Ethiopia, they didn’t leave until 2 million years ago or so—and made it to eastern Asia even later.

Now, evidence from the site of Shangchen, in the Loess Plateau approximately 1200 kilometers southwest of Beijing, is shaking up that view.

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