For a long time, people believed that the Neanderthals had died out shortly after Cro-Magnon, the ancestors of modern-day humans, showed up. However, an international study led by Oxford University suggests that the two species overlapped for up to 5,400 years, allowing plenty of time for the two cultures and genes to mix with one another. For the 6-year study, researchers used improved methods of radiocarbon dating to analyze around 200 different samples of bone, shell and charcoal from 40 important archaeological sites around Europe, from Spain to Russia. These were chosen because they either showed signs of Neanderthal tool-making or because they contained stone tools that were thought to be from early modern humans or Neanderthals.
With the help of mathematical formulas, the team compared the new radiocarbon data with previous findings from studying rock layers to piece together the chronology of the findings. The results reveal that Neanderthals disappeared from Europe between 41,030 and 39,260 years ago, long after early modern humans arrived on the scene. According to the authors, this means that Neanderthals and early modern humans must have overlapped for a significant amount of time, which would give them plenty of time to interact and interbreed with each other. Nonetheless, the researchers emphasize that they weren’t able to figure out exactly where interbreeding may have occurred in Europe, and whether or not it happened in isolated incidents or repeatedly. The researchers say that up to 2% of DNA in today’s non-African humans originally comes from the Neanderthals, which suggests that the two groups did interbreed outside of Africa.
Evidence also hints that Neanderthals may have survived in dwindling populations in pockets of Europe before they finally became extinct. Previous techniques for obtaining radiocarbon dates may have resulted in underestimates of the age of Neanderthal samples, which in turn could have been contaminated with modern material. The researchers used ultrafiltration methods which purify the extracted collagen from bone, which would help avoid the risk of modern contamination. This means that the researchers can confidently say that they’ve finally resolved the timing of the disappearance of the Neanderthals. Of course, the Neanderthals aren’t entirely extinct, since they make up part of the genetic makeup of many modern humans.