Modern humans moved into cave one year after Neanderthals abandoned it

About 10,000 years before modern humans colonised Europe, a small group of them moved into a cave in southern France that had just been abandoned by Neanderthals – but they only stayed there for about 40 years

By Michael Marshall

A small group of modern humans moved into what is now France about 54,000 years ago – which is 10,000 years before our species began spreading across Europe in earnest. The pioneering group only managed to survive in the area for about 40 years, before disappearing.

“It’s not just one wave of modern humans arriving and colonising all Europe, there are probably several attempts,” says Clément Zanolli at the University of Bordeaux in France. “What we have found… is probably one of those attempts, and there are probably other attempts that we did not find yet.”

It isn’t clear why this incursion into Europe was unsuccessful. “Did they go back to where they came from?” asks Zanolli. “Or did they just die there and not survive more than a few decades? It’s impossible to say.”

Zanolli is part of a team that has been excavating at Grotte Mandrin in southern France since 1990. It is a small cave on a hill, overlooking the Rhône valley. Over the years, the team has found nearly 60,000 stone artefacts and more than 70,000 animal remains. Crucially, there are also nine hominin teeth, from at least seven individuals.

The team has used these artefacts, along with dating techniques, to reconstruct which hominins lived at Mandrin. The earliest known inhabitants were Neanderthals, who lived throughout Europe for hundreds of thousands of years until their extinction about 40,000 years ago. Neanderthals lived at Mandrin from more than 80,000 years ago until about 54,000 years ago.

However, one of the teeth belonged to a modern human. It was a baby or “deciduous” tooth, so it belonged to a child. The layer of sediment in which it was found was dated to between 56,800 and 51,700 years ago – probably about 54,000 years ago. The stone artefacts found in this layer were different from those associated with the Neanderthals, and resembled those made by modern humans elsewhere.

In younger layers of sediments, the team again found Neanderthal remains. Signs that the cave was being used by modern humans reappeared after 44,100 years ago. That is about when modern humans entered Europe in a big way.

The first switch from Neanderthals to modern humans happened quickly, says co-author Ludovic Slimak of the University of Toulouse-Jean Jaurès in France.

“Between the last fire in the cave by Neanderthals and the first fire in the cave by Homo sapiens, it’s something like a year maximum time.” The team could tell because they studied pieces of soot from fires, on which layers of calcite had formed that could be precisely dated. The soot and calcite evidence also helped to pin down the length of time the cave was occupied by modern humans to roughly 40 years.

The results are “convincing”, says Katerina Harvati of the University of Tübingen in Germany. “Although the fossil evidence for modern humans consists of a single isolated deciduous tooth, dental remains, including deciduous teeth, have been shown to be highly diagnostic.”

In 2019, Harvati’s team presented evidence of modern humans living in Greece 210,000 years ago. This remains the earliest reported instance of Homo sapiens in Europe, far earlier than the Mandrin population.

Such studies show “the complexity of the process of dispersal and contact”, says Harvati. Instead of a simple story of modern humans entering Europe in one wave and replacing Neanderthals, there were “alternating occupations of geographical regions, occasional  contact and periods of isolation”.

Zanolli’s team found no evidence of cultural exchange between the groups – the later Neanderthals didn’t start making human-style artefacts, for example. Yet given that the two groups were in Mandrin in successive years, “it’s very likely that they met”, says Zanolli.

Harvati agrees. “The co-existence of the two groups could have taken many forms and would not necessarily result in interbreeding or cultural exchange,” she says.

While we don’t know what happened to the modern human group, one possibility is that they were too few to survive on their own. Small groups moving into new areas often don’t survive. “Generally, you need to have social and genetic exchanges with the local population,” says Slimak. “If you don’t have genetic exchanges, you just disappear.”

Journal reference: Science Advances, DOI: 10.1126/sciadv.abj9496

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