Did Neanderthals and the first ancestors of modern man ever meet? The argument has raged among archaeologists and paleontologists for decades.
Now a group of scientists claim to have proof — based on radiocarbon dating of artifact finds in France — that the two distinct groups did indeed share the same space at the same time some 38,000 years ago.
"These data strongly support the chronological coexistence — and therefore potential demographic and cultural interactions — between the last Neanderthal and the earliest anatomically and behaviorally modern human populations in western Europe," they wrote in the latest edition of the journal Nature.
Some scientists have argued that Neanderthals and the first ancestors of modern man existed at the same time — at least for a while — but in different places, while others have argued that Neanderthals died out before modern man came along.
Others still have suggested that they not only met but may even have interbred.
The arguments have ebbed and flowed for generations — fueled from time to time by new artifact finds, mainly from Kenya's Rift Valley.
But the team of scientists writing in Thursday's edition of Nature believe they may have settled the dispute with analysis of tools discovered at different depths in the cave of the Grotte des Fees at Chatelperron in central France.
In the cave a layer of tools from the later so-called Aurignacian culture — named after Aurignac near Spain where they were first discovered — were found sandwiched between two layers of tools attributed to earlier Neanderthals.
Aurignacian tools are more sophisticated and deemed to have been made by the first modern humans.
The scientists, led by Paul Mellars from Cambridge University, said the layers suggested that not only had the two groups been around at the same time but that they must have shared the same space — at least for a while.
Radiocarbon dating of some of the bone fragments from the different layers confirmed the observational conclusions.
The scientists suggested that encroaching cold may have made the Aurignacians move towards the warmer coast from central Europe and at the same time encouraged the Neanderthals to move even further south where it would have been even warmer.
When the weather warmed again in later generations the population flow was reversed — suggesting that the ancestors of modern man may have been better equipped to deal with colder climates than the last groups of Neanderthals, they said.