Neanderthals, the extinct human species, are believed to have lived together with the modern humans for around 5,000 years in Europe.
Scientists have previously agreed that Neanderthals lived in Europe and in parts of Asia around 200,000 years ago, but the date of their extinction is disputed by many researchers.
Previous studies suggest that modern humans and Neanderthals co-existed for as less as 500 years. However, taking help from the new radiocarbon dating techniques, a group of international researchers suggest that Neanderthals died around 40,000 years ago but lived and mixed with modern humans for over 5,000 years in Europe before becoming extinct.
The co-existence of the two human species means that they shared a culture and scientists suggest that interbreeding between the two species also occurred. The researchers say that the genes of Neanderthals can be found in the DNA of modern humans.
"We believe we now have the first robust timeline that sheds new light on some of the key questions around the possible interactions between Neanderthals and modern humans," says Thomas Higham, an archaeologist at the University of Oxford who led the study.
Recent studies indicate that up to 2.1 percent of the DNA of modern non-African humans is derived from Neanderthals. Professor Tom Higham of the University of Oxford, who is the lead researcher of the study, says that in a way the Neanderthals are not extinct but "they carry on in us today."
Scientists believe that interbreeding between the Neanderthals and modern humans probably occurred initially in Asia, when modern humans started to leave Africa about 60,000 years back. The researchers also believe that the two species may have been in some sort of contact for around 20,000 years, which is much longer than 5,000 years as previously estimated in Europe.
For the purpose of the study, the scientists examined about 200 fossil samples from over 40 Neanderthals sites in Europe ranging from Russia and Spain. These samples are important in the Neanderthal timeline, but they do not act as evidence that the two human species lived together. Neanderthals are said to have lived in small groups before they died out altogether.
Scientists are unsure about the extinction of the Neanderthals, but some theories suggest that they were unable to adapt to climatic changes and increased competition for food and other resources from modern humans. Some scientists also refute that the Neanderthals were killed by modern humans or were the victims of the diseases brought in by modern humans. Scientists also opine that the extinction process of the Neanderthals was not rapid but gradual.
The study has been published in the journal Nature.