Scientists Document Most Recent Date For Neandertals

The team's findings -- published in the Oct. 26 issue of the prestigious journal, Proceedings of the National Academy of Sciences -- may force other scientists to rethink theories of Neandertal extinction, intelligence and contributions to the human gene pool. The research on Neandertal fossils from the Vindija cave site in Croatia also casts doubt on the theory that the Iberian Peninsula was the Neandertals' last refuge.

"Most scientists would have expected to find the latest Neandertal in southwest Europe, rather than in central Europe," said paleontologist Fred H. Smith, a research team member and chairman of the Anthropology Department at Northern Illinois University. "The new radiocarbon dates suggest Neandertals would have coexisted with early modern humans in central Europe for several millennia."

"The extinction of the Neandertals by early modern humans, whether by displacement or population absorption, was a slow and geographically mosaic process," said team member Erik Trinkaus, an anthropologist at Washington University in St. Louis. "The differences between the two groups in basic behavior and abilities must have been small and rather subtle."

Using direct accelerator mass spectrometry radiocarbon dating, team member Paul Pettitt and colleagues at Oxford University (England), determined that two pieces of Neandertal skulls from the Vindija cave site are between 28,000 and 29,000 years old.

The new Croatian dates refute previous evidence indicating central European Neandertals had disappeared by 34,000 years ago. Neandertals are commonly portrayed as prehistoric humans of limited capabilities who were rapidly replaced and driven to extinction by superior early modern humans, once the latter appeared in Europe. Scientists surmised that modern humans from the Near East moved first into central Europe and then into western Europe, pushing Neandertals into the Iberian Peninsula at the extreme southwest portion of the continent, where the Neandertals died off about 30,000 years ago.

Coupled with his earlier work at Vindija, Smith said the new radiocarbon dates call into question this pattern of Neandertal migration and extinction. In his earlier work, Smith also argued that late Neandertal fossils from the cave site had some modern human anatomical characteristics.

The Croatian dates indicating thousands of years of coexistence between Neandertals and early modern humans in central Europe cast in a different light a study in which scientists compared the DNA of a Neandertal with the DNA of contemporary humans. Published two years ago, the study concluded that, while Neandertals and early modern humans may have coexisted in Europe, they probably didn't mate.

"The new dates, in my opinion, add some support to the idea that there was probably a good deal of genetic exchange between Neandertals and modern humans," Smith said. "When you look at the anatomy of early modern Europeans, you also find a number of features that are hard to explain unless you allow the Neandertals some ancestral status. And actually, the Neandertal mitochondrial DNA is not completely out of the modern human range, just on its extreme periphery."

Moreover, the finding last year of a 24,500-year-old early modern human child with distinctive Neandertal characteristics in Portugal, published by Trinkaus and European colleagues in June 1999, strongly supports the conclusion that Neandertals and early modern humans both could and did share mates when they came into contact.

"Not only do we have the skeleton of a child in Portugal showing characteristics of common descent, but now we have evidence of the two groups coinciding in central Europe for several millennia allowing plenty of time for the populations to mix," said Trinkaus, a Washington University professor of anthropology in Arts and Sciences.

The new Croatian findings also raise the question of who created the ancient tools unearthed at the Vindija cave site, located about 34 miles north of the Croatian capital of Zagreb. Neandertals are commonly associated with relatively crude stone tools, while early modern humans made more sophisticated stone and bone tools. The Vindija site produced both kinds of tools, including a beveled bone probably used as the tip of a spear. "The big question is: 'Why do we have a combination of tools?' " Smith said.

"It's possible Neandertals developed all these tools or got the bone tools through trade with moderns," he added. Both of these possibilities run counter to the generally accepted idea that Neandertals could not produce bone or use more sophisticated stone and bone tools.

Smith and Trinkaus conceived of the research project, secured permission for dating of fossils and assembled the research team. Other team members are Ivor Karavanic at the University of Zagreb and Maja Paunovic of the Croatian Academy of Sciences.