|FEATURES Winter 2000|
By studying their bones, Professor Erik Trinkaus has learned much about Neandertals and early modern humans. His discoveries are changing our perceptions of who they were.
Neandertal man he is sometimes called. In the popular consciousness he is the caveman of cartoons and B-grade filmsbent-kneed, hunch-shouldered, low-browed, and hairy, wielding a club while he eats oversized haunches of meat.
But such stereotypes are completely unfounded, says paleoanthropologist Erik Trinkaus. In fact, Neandertals, who lived between 100,000 and 28,000 years ago, were not all that different from us.
Trinkaus, professor of anthropology in Arts & Sciences, has made a career of studying Neandertal fossils. He's learned a lot from their bones.
"As a graduate student," he says, "I realized that I could combine biology with my interest in the past and in human behavior, and use them all to try to understand what was going on in the fairly distant human past."
At the same time, he became interested in Neandertals. "A number of fossils had been discovered in Europe and the Middle East. They had been a hot topic of discussion for most of the 20th century. But in the 1970s, no one really cared very much about them. The real focus of human-origins research was on the early phasesanything less than a million and a half years old just wasn't sexy enough."
But this academic climate left open many opportunities to study more recent fossils, says Trinkaus. "I was actually told, when I was a graduate student, 'Why do you want to work on Neandertals? We know everything there is to know about them.' The fact is, there was a tremendous amount of research that had never been done."
Trinkaus can no longer avoid the question of origins because his recent research is so relevant to the subject ... and points inevitably to assimilation.
We know now that Neandertals were short, stocky, and incredibly strong. Their brow ridge was heavy, their chins almost nonexistent, their noses quite large. Their build was an adaptation to the climate, for Neandertals lived primarily in cold regions. They were successful hunters, but their lives were difficult, the threat of injury or starvation ever present. They developed tools and weapons and strong survival skills. They cared for the injured and the lame in their small communities. They wore ornaments made of bone and animal teeth. They buried their dead.
This is the story told by their bones.
Trinkaus has interpreted much of this story from the wear and tear on Neandertal bodies. For instance, an unusually large number of Neandertal skeletons have healed broken bones. "It's a feature of survival," says Trinkaus. "There was a very high risk of injury, but they were surviving."
Trinkaus recently co-authored, with Fred Smith, distinguished research professor and chair of the Department of Anthropology at Northern Illinois University, a study (which was conducted at Oxford University along with researchers there) of Neandertal bones from Croatia. By measuring the isotopic ratios of nitrogen-15 in the bones, the researchers determined that Neandertals ate a diet rich in meat. The ratios were similar to those found in the bones of top-level animal predators, such as lions. The findings also indicate a high degree of social organization, necessary for small communities to hunt large mammals successfully, and refute the theory that Neandertals were primarily scavengers.
The Croatian Neandertal remains are significant for another reason. The researchers dated the remains, discovered in a cave at Vindija, to only 28,000 years agothat's 2,000 years or more later than scientists had previously believed the last Neandertals became extinct. What's more, early modern humans, theorized by many scientists to have driven Neandertals to extinction, lived in relative proximity to Vindija for thousands of years. This proximity suggests contact and even some degree of assimilation between the two groups.
"It is interesting," says Smith, "that in this time period where there is the possibility of overlap between early moderns and Neandertals, you begin to see Neandertal culture in Europe taking on some characteristics of early modern culture. You also find, at Vindija, biological characteristics that reflect modern human morphology. For example, the faces are smaller, the brow ridges are smaller, there is more of a chin. To me, all of those things suggest a good bit of cultural and biological exchange between the two populations."
These and other discoveries have thrown Trinkaus into the midst of a scientific feud. The debate revolves around two related questions: Were Neandertals displaced or assimilated by early modern humans, and are they our ancestors?
"Over the years," Trinkaus says, "I have avoided, to a large extent, the argument about ancestry. My focus has been on the biologywho they were rather than how they relate to us."
Trinkaus can no longer avoid the question of origins because his recent research is so relevant to the subject ... and points inevitably to assimilation. He says, "If you look at the current body of knowledge, both in human paleontology and genetics, I think the issue really is: To what degree were archaic humans like Neandertals assimilated? And how much did it vary geographically?"
"Erik is at the stage where his work defines much for the research agenda of the biology of Neandertals and other early modern humans," says Richard Smith, professor and chair of anthropology in Arts & Sciences. "He's extremely influential and creative. It's exciting to have him around."
"Erik has provided very good description and analyses of some very, very important fossil material," says Fred Smith. "The Shanidar sample from Iraq, for example, which Erik studied in the 1970s and '80s, was crucial to how we view Neandertals today."
Early modern humans, who arrived in Europe about 35,000 years ago, have been somewhat neglected by paleontologists. "In the 1990s," says Trinkaus, "it became increasingly apparent to me that we knew more about Neandertal biology than we did about early modern human biology, the common assumption being that they're just like modern humans. But they are significantly different from us in a variety of characteristics. Starting in the mid-'90s, I began several projects that involved the same biological analyses on early modern human fossil remains that I had done on Neandertals."
The first of these studies was on materials from the Middle East. Then Trinkaus was invited by a Czech archaeologist to help study some early modern remains, dating to about 25,000 to 27,000 years ago, from the Pavlov Hills in the Czech Republic. What he found there was very exciting.
"These are incredibly rich sites," he says. "They have the world's oldest intentionally fired ceramics. They have the world's oldest evidence of textiles. We've found that some of the differences between these early modern humans and Neandertals, in terms of things like strength and endurance, are much less than we originally thought. They are very strongly built."
Although the biology of the Croatian and Czech fossils seems to indicate some assimilation between Neandertals and early modern humans, the findings are inconclusive.
And there the question may have remained, tantalizing yet unanswered, but for an extraordinary find in 1998. Portuguese archaeologists discovered the almost complete skeleton of a child, about 4 years old when he died, who was buried nearly 25,000 years ago. They invited Trinkaus to examine the skeleton.
"I started analyzing it and things started seeming strange to me," he says. "I thought it was an early modern human. Then it suddenly occurred to me, 'Some of these features look like a Neandertal. There's something wrong here.' I can explain it in no other way but that it's a hybrid. The child is very much a mosaic."
The announcement quickly became world news. While the media focused on the interbreeding aspect, Trinkaus was more intrigued with the social and biological implications of the find.
"The burial was of the kind associated with early modern humans. The anatomy was mixed, and so our interpretation was that not only were Neandertals absorbed into the population and treated like people, but the offspring of these so-called mixed marriages were clearly treated with full respect. A child would not be given an elaborate burial ritual unless that individual was considered an important member of the social group. We looked at it very much in a behavioral sense, what this told us about what happened when Neandertals and early modern humans met, at least in this region."
The Portuguese find does not put an end to the controversy. Some anthropologists dispute Trinkaus' conclusions, but this is not a bad thing, says physical anthropologist Richard Smith. "Controversy is fundamental to our area of research. In anthropology, controversy is a way of working through the many implications of important ideas. It's controversial because it's an important issue. Erik's positions are carefully thought out and highly defendable."
Aside from his teaching responsibilities, Trinkaus plans to publish more detailed descriptions of both the Portuguese child and the Czech fossils. A third project involves a study of some 24,000-year-old burials in Russia. Each of his projects includes an international team of experts, and he relishes the exchange of ideas.
"I've got plenty to keep me going, even without any more fossils," Trinkaus says with a smile. "They're still digging at the Portuguese site. They might find more fossils. We'll just have to see."
For more information, contact: http://artsci.wustl.edu/~anthro/blurb/b_trink.html.
Photo left: Erik Trinkaus, professor of anthropology in Arts & Sciences, examines a Neandertal skull.
Displacement vs. Assimilation
The disappearance of the Neandertals has long intrigued scientists.
The predominant theory used to be that early modern humans arrived in Europe and quickly displaced the Neandertals, who were not physically, mentally, or culturally equipped to compete with the newcomers. The Neandertals soon died out or were pushed to the fringes of Europe (such as the Iberian Peninsula), where some of them survived for a couple thousand more years before finally becoming extinct.
The two groups were long viewed as separate species, the Neandertals short and robust with protruding brows and receding chins, the early modern humans tall and gracile with high foreheads and delicate features. The early moderns had art and language. Many scientists believed the Neandertals had neither. The early moderns evolved in tropical Africa and quickly spread, remarkably adaptable, throughout the world. The Neandertals were adapted to colder climes and represented an offshoot-a dead limbon the human family tree.
But recent discoveries have challenged this view.
"There no longer appears to be that sudden kind of disappearance," says Trinkaus. "They were coexisting."
And the species question? "It's a name game," he says.
A recent study of Neandertal DNA found sequences outside the range of modern human variation. While many people concluded from this that Neandertals could not be our ancestors, others argued that the fact that Neandertal DNA is no longer to be found in the human population does not necessarily exclude them from our ancestry. Those sequences could have been bred out over the tens of thousands of years since Neandertals became extinct. Even the discovery of an apparent Neandertal-early-modern-human hybrid in Portugal does not answer the question. Some Neandertals and early modern humans may have interbred, and they mayor may nothave surviving descendants.