Stone tools unearthed in China suggest that ancient humans moved around the world much earlier than previously thought, according to new research published in the journal Nature. The remains — which were found by a group of international researchers — date back 2.12 million years and are the earliest evidence ever found of humans outside of Africa.
The team made the discovery when they uncovered dozens of quartz and quartzite stones on the Loess Plateau at Shangchen, China. Current estimates suggest hominins originated in Africa roughly 6 million years ago and then did not migrate out until millions of years later. That is supported by the current fossil record, which shows hominin artifacts dating back 1.5 to 1.7 million years ago in numerous spots outside of Africa.
In fact, before this new finding, the earliest evidence of hominins outside of the continent came from a skeleton found in the Republic of Georgia that dated back 1.85 million years.
Though the stones uncovered in the study look like rocks at first glance, close study revealed they are flaked in a certain way to create specific lines. In addition, they were also found in a stone-free landscape. That suggests they were not worn down as a result of natural processes, but rather by early humans.
This discovery is important because, as it suggests human ancestors left Africa 10,000 generations earlier than previously thought, it changes what researchers know about our species’ past. While scientists are not yet sure what hominins made the ancient tools, they plan to follow up and see what else they can find.