Neanderthals and humans lived side by side in France and northern Spain for up to 2,900 years, modeling research suggested Thursday, giving them plenty of time to potentially learn from each other or even breed. While the study, did not provide evidence of direct human interaction with Neanderthals around 42,000 years ago, previous genetic research has shown that they must have occurred at some point.
Research by Swedish palaeogeneticist Svante Paabo, who won the Nobel Prize in Medicine last week, helped reveal that people of European descent – and almost everyone around 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 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 has suggested that modern humans and Neanderthals walked the Earth at the same time for thousands of years. To learn more, the Leiden-led team looked at the radiocarbon dating of 56 artefacts – 28 each for Neanderthals and humans – from 17 sites across 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 potential data ranges. ‘Never Really Extinct’ They then used optimal linear estimation, a new modeling technique they adapted from biological conservation sciences, to get the best estimate of when the last Neanderthals lived in the region. Djakovic said the “basic assumption” of the technique is that it is unlikely we will ever discover the first or last members of an extinct species. “For example, we will never find the last woolly rhinoceros,” he told, adding that “our understanding is always fragmented”.
Modeling found that Neanderthals became extinct in the area between 40,870 and 40,457 years ago, while modern humans first appeared about 42,500 years ago. That means the two species lived side by side in the region for 1,400 to 2,900 years, the study said. During this time, there are indications of a major “diffusion of ideas” by both humans and Neanderthals, Djakovic said. The period is “associated with substantial changes in the way people create material culture,” such as tools and ornaments, he said.
He also added that there was a “quite major” change in the artifacts produced by Neanderthals, which became much more similar to those made by humans. Given the changes in culture and evidence in our own genes, the new timeline could further bolster the leading theory of the end of the Neanderthals: mating with humans. Breeding with a larger human population may have meant that over time, Neanderthals were “effectively absorbed into our gene pool,” Djakovic said. “When you combine that with what we know now that most people living on Earth have Neanderthal DNA you could argue that in a sense they never really died out.”
