The discovery of a hoard of ancient human teeth in a Chinese cave has forced scientists to reconsider our species’ relations with our closest evolutionary cousins, the Neanderthals. The find, revealed in the science journal Nature, shows modern humans must have left their African homeland and reached southern China more than 80,000 years ago.

This unexpectedly early date contrasts with our ancestors’ far more recent arrival in Europe - about 45,000 years ago – and suggests Homo sapiens was prevented, for some reason, from moving there for tens of thousands of years. Anthropologist María Martinón-Torres, from University College London – a member of the team that made the discovery – is confident of the reason. She blames the Neanderthals.

“Homo sapiens evolved in Africa and emerged from the continent about 100,000 years ago and swept eastward with little apparent resistance from other hominid species they encountered. But when they headed north, they reached the Levant and met the Neanderthals at the southern edge of their European domain. And there they stopped our spread. Essentially Europe was too small for the both of us.”

Neanderthals were experienced hunters and gifted foragers, and had controlled Europe for hundreds of thousands of years. They were therefore able to keep us at the edge of Europe for 40,000 years, added Martinón-Torres. “It was not a matter of physical confrontation, however. It was a matter of who was best able to exploit resources. They had much more experience of the harsher, colder conditions that existed in Europe. I think we have underestimated them. They were not grunting, ignorant cavemen. They were our equals.”

Wu Liu, who led the team that found the teeth. Photograph: Xinhua/Rex

The discovery of the teeth – 47 found at Fuyan cave in Daoxian, in southern China – was made by a team led by Wu Liu of the Chinese Academy of Sciences, Beijing. The teeth were beneath rocks over which stalagmites had grown. Dating techniques indicate the stalagmites are at least 80,000 years old. And so everything below that layer must be older. (Teeth are made of dentine and enamel and the latter is the body’s hardest tissue. As a result, teeth are often preserved at prehistoric sites while other body parts decay and leave no trace.) In fact, the teeth could be up to 125,000 years old, researchers suggest. Nevertheless they closely resemble those of modern Europeans. “The Fuyan teeth indicate that modern humans were present in southern China between 30,000 to 60,000 years earlier than in the eastern Mediterranean and Europe,” states archaeologist Robin Dennell in a commentary article about the find in Nature. The difference in timescale is remarkable. Modern humans were thought to have left their African homeland about 60,000 to 70,000 years ago, eventually reaching Europe about 45,000 years ago, the earliest date that scientists have established for the presence of Homo sapiens there. It then took a further 15,000 to 25,000 years to complete our conquest of Europe. However, the new study suggests the real figure is far higher and modern humans had to wait between 40,000 and 50,000 years before they got into Europe.

In contrast to our progress northward, modern humanity’s progress eastward was unexpectedly rapid. However, not every scientist blames the Neanderthals for blocking our progress in Europe. “One possibility is that an early dispersal headed eastwards through Arabia away from Europe and that the colonisation of Europe through the Levant occurred via a later dispersal,” said Professor Chris Stringer, of the Natural History Museum, London.

“In addition, the climate in Europe was relatively cold and inhospitable then,” he said. “We were not properly adapted to conditions and couldn’t get a toehold – and, of course, the Neanderthals were there already.”

However, when modern humans did arrive in Europe, they made remarkable progress. Within a few thousand years, they had settled across the continent while the Neanderthals had disappeared. As to the causes for this rapid extinction, researchers point to the harsh climate Neanderthals had endured in Europe for the previous 200,000 years, when the continent was swept by ice ages and intense cold. Conditions eventually took their toll and numbers of Neanderthals dwindled. Tribes got smaller and smaller and their genetic diversity was compromised.

“Essentially, Neanderthals were eventually left in a genetically exhausted state,” said Martinón-Torres. “When we did get into Europe there were hardly any of them left. The rest went quickly after that.”