Modern humans were living in what is now China by 45,000 years ago. The finding means our species reached the area thousands of years earlier than generally thought, possibly via a northerly route through modern-day Siberia and Mongolia.

A team co-led by Francesco d’Errico at the University of Bordeaux in France re-examined an archaeological site called Shiyu in northern China. It was originally excavated in 1963 during the unrest of China’s cultural revolution. “This was not the best moment to find such an important site,” says d’Errico.

Shiyu is an open-air site in a river gully. It holds a 30-metre-deep deposit of sands and other sediment, which the original excavators divided into four horizontal layers, the second from bottom of which was found to hold evidence of human occupation.

The excavators found over 15,000 stone artefacts and thousands of animal bones. There was also a single piece of hominin skull, which anthropologist Woo Ru-Kang identified as a modern human (Homo sapiens).

Some of the artefacts were later transferred to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. But those left at the local facilities – including the hominin bone – were lost. “We have perhaps 10 per cent of the stone tools,” says d’Errico.

D’Errico and his colleagues have re-excavated Shiyu to determine its age. They dated 15 samples of sediment using a technique called optically stimulated luminescence, and carbon-dated 10 animal bones and teeth. The hominin layer is about 44,600 years old.

D’Errico is confident that the skull was correctly identified, as the excavators were “knowledgeable”.

The Shiyu hominins were probably H. sapiens, says Arina Khatsenovich at the Institute of Archaeology and Ethnography in Novosibirsk, Russia, who was not involved in the study.

As such, the new study implies modern humans had reached northern China about 45,000 years ago. This pushes back our species’ arrival in China by about 5000 years. D’Errico argues the next oldest H. sapiens site in China is Tianyuan cave, which is 40,000 years old.

Some researchers have claimed our species arrived earlier, potentially up to 260,000 years ago. But d’Errico points out that researchers have critiqued much of the evidence for such an early human presence in the region.

It may be that, as humans entered Asia from Africa, they spread out via multiple routes, says Khatsenovich. As well as exploring the tropical southern regions of Asia, they also went further north. Khatsenovich says there are signs of a modern human presence in this region, including at Obi-Rakhmat Grotto in Uzbekistan from 48,800 years ago. It may be that our species reached Shiyu, and China, via this northern route.

As modern humans reached new areas, they encountered hominins that already lived there like the Neanderthals and, further east, the Denisovans. Genetic evidence has shown we interbred with them. There may also have been cultural exchanges: the artefacts at Shiyu include some that look more like archaic human tools.

There is also evidence of long-distance exchanges. The Shiyu team identified four pieces of obsidian, a volcanic glass. They were able to trace them to sites 800 and 1000 kilometres north-east of Shiyu. D’Errico says it is unlikely the inhabitants travelled these distances themselves, so they were probably part of a network of groups. In line with this, Khatsenovich says some of the Shiyu artefacts resemble pieces found in Korea, far to the east.