Neanderthals Went Extinct Earlier Than Thought, Suggest New Radiocarbon Dating Methods

Neanderthals may have gone extinct even earlier than previously believed, scientists have announced, according to LiveScience.com. Investigators said the findings suggest that Neanderthals didn't coexist with modern humans as long as has been suggested in the past.

Scientists have long known that modern humans once shared the planet with numerous Homo sapien adjacent lineages, including Neanderthals, our closest known extinct relatives. However, just how long Neanderthals and modern humans interacted, or even possibly interbred, remains a topic of heated debate.

To finally answer the question of just how much modern humans and Neanderthals interacted and interbred, if at all, an international team of researchers investigated 215 bones previously excavated from 11 sites in southern Iberia, modern-day Spain. Scientists say that Neanderthals reached Europe before modern humans, and prior findings had suggested the last of the Neanderthals remained in southern Iberia until roughly 35,000 years ago, possibly sharing the region with modern day humans for a few thousand years.

The data collected suggests that modern humans and Neanderthals may have lived in the area at entirely different time periods, possibly never crossing paths there. However, researchers say that these findings don't rule out the possibility of modern humans and Neanderthals having sex. Rather, the findings indicate that interbreeding must have occurred earlier, before modern humans entered Europe, researchers said.

"Our work suggests that at present, it is unlikely that Neanderthals survived any later in this area than they did elsewhere in mainland Europe," said researcher Thomas Higham at the University of Oxford in England.

"The genetic evidence for interbreeding - 1 to 4 percent Neanderthal DNA in present-day modern humans - suggests that interbreeding probably occurred before the period we are looking at in the Levant, the region around Israel and Syria, when modern humans first migrated out of Africa," researcher Rachel Wood, an archaeologist and radiocarbon specialist at Australian National University in Canberra, told LiveScience.

New radiocarbon dating techniques aided the researchers in making these relavatory discoveries, Wood added.

She said the most surprising thing ""was the enormous difference that the ultrafiltration dating made to the chronologies of the sites we looked at," Wood said. "At other sites in Europe, we have seen that this improved method of dating bone makes a difference, making old bones older. However, we do not normally see such consistently large differences. This is probably because the preservation of the organic materials - bone and charcoal - that are normally radiocarbon dated is really poor in warm climates like southern Spain."

Further analysis of the remaining samples revealed that they were at least 10,000 years older than scientists previously speculated. The Neanderthal bones were now close to or more than 50,000-years-old, the upper limit for radiocarbon dating, according to LiveScience.com.

"Our results cast doubt on a hypothesis that has been broadly accepted since the early 1990s - that the last place for surviving Neanderthals was in the southern Iberian Peninsula," Wood said. "Much of the evidence that has supported this idea is based on a series of radiocarbon dates, which cluster at around 35,000 years ago. Our results call all of these results into question."

The new findings suggest that modern humans and Neanderthals didn't coexist for around 1,000 years as previously thought.

The results of our study suggest that there are major problems with the dating of the last Neanderthals in modern-day Spain," Higham said. "We now have to look very cautiously at the model of late Neanderthal survival in southern Iberia and focus our efforts on more rigorous dating programs."