Our ancient ancestors lived in China, too.
Ancient humans appear to have reached northwestern China about 2.1 million years ago, and they lived there for hundreds of thousands of years, according to a new study published Wednesday in Nature. It suggests that hominins migrated out of Africa much earlier, and spread much farther east, than once thought.
Previously, the earliest ancient-human presence outside of Africa had been a Homo erectus fossil found in a cave in Dmanisi, Georgia. It was dated to 1.85 million years ago. This newly discovered community of early humans lived roughly 250,000 years earlier than that group, and did so 3,500 miles to the east.
The research was led by Zhaoyu Zhu, an archeologist and climatologist at the Chinese Academy of Science. Zhu and his team have spent the last 13 years excavating a unique site on China’s Loess Plateau, a rare spot protected from erosion, glaciation, and continually buried in wind-blown sand over the last several million years.
While the new paper identifies a human presence, the researchers have not yet found any early human fossils at the site. They have unearthed a wealth of early stone tools left behind by our ancestors, buried under many layers of solidified sand. These artifacts are mostly chipped flakes of stone, a type of primitive blade created by smashing two river-smoothed cobbles together. Hominins in Africa are known to have used this technology during the same period.
Claiming an ancient-human presence from a bunch of stone flakes could prove controversial among some researchers, who only feel confident dating an ancient-human presence when they find the remains of an early human, like teeth, a jaw bone, or ancient DNA.
But both the paper’s authors and outside experts told me they felt comfortable asserting that ancient humans lived on this site.
“It comes down to two general points,” said John Kappelman, a professor of anthropology and geology at the University of Texas at Austin who was not connected to the research. First, the stone tools “look like they were produced by humans,” he told me. They also show evidence of manufacture and maintenance. Some flakes have an almost serrated edge, suggesting that their creator smashed them against a cobble multiple times in order to improve them. Others “appear to show re-sharpening or sharpening,” he said, meaning their users attended to their tools and tried to improve them.
“Hominin remains are incredibly scarce,” he continued. “Their skeletons are very fragile, preservation is very rare, and they were not very common. In contrast, a single hominin can generate thousands of stone tools in a lifetime. Additionally, fossils will never indicate the first actual appearance of an animal—the first recorded appearance is always later than the first actual appearance, no matter whether it’s a hominin or a hippopotamus.”
