Neanderthals and modern humans not only coexisted for thousands of years long ago, as anthropologists have established, but now their little secret is out: They also cohabited.
At least that is the interpretation being made by paleontologists who have examined the 24,500-year-old skeleton of a young boy discovered recently in a shallow grave in Portugal. Bred in the boy's bones seemed to be a genetic heritage part Neanderthal, part early modern Homo sapiens. He was a hybrid, they concluded, and the first strong physical evidence of interbreeding between the groups in Europe.
"This skeleton demonstrates that early modern humans and Neanderthals are not all that different," said Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis. "They intermixed, interbred and produced offspring."
Although some scientists disputed the interpretation, other scientists who study human origins said in interviews last week that the findings were intriguing, probably correct and certain to provoke debate and challenges to conventional thinking about the place of Neanderthals in human evolution.
Neanderthals and modern humans were presumably more alike than different, not a separate species or even subspecies, but two groups who viewed each other as appropriate mates.
Recent DNA research had appeared to show that the two people were unrelated and had not interbred. Neanderthals lived in Europe and western Asia from 300,000 years ago until the last of them disappeared on the Iberian peninsula about 28,000 years ago. In the prevailing theory today, modern humans arose in Africa less than 200,000 years ago and appeared in great numbers in Europe, starting about 40,000 years ago.
The new discovery could, at long last, resolve the question of what happened to the Neanderthals, the stereotypical stocky, heavy-browed "cave men." They may have merged with modern humans, called Cro-Magnons, who appear to have arrived in Europe with a superior tool culture. In that case, some Neanderthal genes survive in most Europeans and people of European descent.
The skeleton of the boy, buried with strings of marine shells and painted with red ocher, was uncovered in December by Portuguese archaeologists led by Joao Zilhao, director of the Institute of Archaeology in Lisbon.
Realizing the potential significance, Zilhao called in Trinkaus, an authority on Neanderthal paleontology, who went to Lisbon and examined the bones in January.
The boy, who was about 4 years old at death, had the prominent chin and other facial characteristics of a fully modern human. But his stocky body and short legs were those of a Neanderthal. Trinkaus compared the limb proportions with those of Neanderthal skeletons, including some children. He said he was then sure of the skeleton's implications.
"It's a complex mosaic, which is what you get when you have a hybrid," Trinkaus said. "This is the first definite evidence of admixture between Neanderthals and European early modern humans."
The age of the skeleton, determined by radiocarbon dating, showed that full Neanderthals had apparently been extinct for at least 4,000 years before the boy was born. "This is no love child," Trinkaus said, meaning that this was not evidence of a rare mating but a descendant of generations of Neanderthal-Cro-Magnon hybrids.
Trinkaus and Zilhao have completed a more detailed scientific report to be published soon in the Proceedings of the National Academy of Sciences. DNA tests on the skeleton have not yet been done.
Other Neanderthal specialists reacted favorably to the discovery. Fred H. Smith of Northern Illinois University in De Kalb called it "very convincing and absolutely right."
Smith noted that he had come upon other skeletal material in Central Europe that raised the possibility of interbreeding between the groups.
Though most scholars in the field will probably accept the possibility of interbreeding, he said, a significant number will probably not.
Pub Date: 4/25/99