Neanderthals and humans coexisted in France and northern Spain for up to 2,900 years, model research suggested Thursday, giving them plenty of time to potentially learn from or even breed with one another.
While the study, published in the journal Scientific Reports, found no evidence that humans interacted directly with Neanderthals around 42,000 years ago, previous genetic research has shown that they must have done so at some point.
Research by Swedish paleogeneticist Svante Paabo, winner of the Nobel Prize in Medicine last week, helped reveal that people of European descent – and almost everyone in the world – have a small percentage of Neanderthal DNA.
Igor Djakovic, a PhD student at Leiden University in the Netherlands and lead author of the new study, said we know that humans and Neanderthals “met and integrated in Europe, but we have no idea in which specific regions this actually happened.” .
Exactly when this happened has also proven elusive, although previous fossil evidence suggests that modern humans and Neanderthals lived on Earth at the same time for thousands of years.
To find out more, the Leiden-led team examined the radiocarbon dating of 56 artifacts – 28 each for Neanderthals and humans – from 17 sites in France and northern Spain.
Artifacts included bones as well as distinctive stone knives believed to have been made by some of the last Neanderthals in the region.
The researchers then used Bayesian modeling to narrow down the potential date ranges.
– ‘Never really went out’ –
Then they used optimal linear estimation, a new modeling technique they borrowed from biological conservation science, to get the best estimate for the time when the region’s last Neanderthals lived.
Djakovic said the “basic assumption” of this technique is that we’ll likely never discover the first or last members of an extinct species.
“For example, we will never find the last woolly rhino,” he told AFP, adding that “our understanding is always fragmented.”
Modeling found that Neanderthals became extinct in the region between 40,870 and 40,457 years ago, while modern humans first appeared around 42,500 years ago.
This means the two species coexisted in the region between 1,400 and 2,900 years, the study says.
During this time, there is evidence of a large “spreading of ideas” among both humans and Neanderthals, Djakovic said.
The period is “associated with major changes in the way people produce material culture,” such as tools and ornaments, he said.
There was also a “quite serious” change in Neanderthal-made artifacts, which began to look much more like human-made ones, he added.
Given the shifts in culture and the evidence in our own genes, the new timeline could further bolster a leading theory for the end of Neanderthals: human mating.
Propagating with the larger human population could have meant that Neanderthals “were effectively swallowed up into our gene pool” over time, Djakovic said.
“Combining that with what we know today — that most people on Earth have Neanderthal DNA — you could argue that in a sense they never really went extinct.”
