Learning to Love Neanderthals

Does the 25,000-year-old body of a child found in Portugal make it more likely that they are our ancestors?

By Robert Kunzig|Sunday, August 01, 1999
RELATED TAGS: ARCHAEOLOGY
What you want, when you hold a pendant fashioned 35,000 years ago by a Neanderthal—a fox's tooth with a tiny hole for a leather string—what you want is something only the movies can give. A close-up, in the lab's neon light, on the mottled canine between your fingers, the focus so tight you can see the scratches made by the stone tool. The picture fades, and next you see the same tooth in different hands, stronger ones with beefy fingers: the hands of the craftsman. He is piercing the tooth with a sharpened piece of flint. Behind him squats a rough tent of hides stretched over mammoth tusks; behind that the dark mouth of a cave. Before and below him a river meanders lazily between birches and willows. Reindeer graze on the far bank. On an early morning in spring, in northern Burgundy during the Ice Age, the light coming in low over the far bluff catches the craftsman's pale, weathered face. It is a human face. The eyes, under the jutting brow, are human eyes, alive with concentration, with memories of other seasons at this place, with intelligence and hope.

No, hold it: Maybe those Neanderthal eyes are blank as a cat's, all surface, with nothing behind them but dumb instinct and a bit of animal cunning—no memories, no plan, no clue.

Back to spring 1999 and the lab, at a modern campus of the University of Paris. An archeologist named Dominique Baffier holds the tooth.

For the past few days newspapers the world over have been reporting the discovery in Portugal of the skeleton of a 4-year-old child, dead for 25,000 years. The discoverers, led by Portuguese archeologist João Zilhão, are making a ground-breaking claim, that the skeleton shows traces of both Neanderthal and modern human ancestry, evidence that modern humans did not simply extinguish the Neanderthals, as many researchers had come to think. Instead the two kinds of human were so alike that in Portugal, at least, they intermingled—and made love—for thousands of years.

The claim is controversial. So, too, and for similar reasons, is the fox tooth Baffier is holding. A collection of such ornaments is arrayed on the table in front of her, along with delicate bone tools—awls for punching through animals hides, needles for sewing or perhaps for pinning up hair. All these artifacts were dug from the mouth of a limestone cave four decades ago at Arcy-sur-Cure, a hundred miles southeast of Paris. Just in the past year, though, the Arcy artifacts have become the subject of heated debate. Zilhão, Baffier, and several French colleagues claim the artifacts show that Neanderthals were not inferior to our ancestors, the Cro-Magnons. Independently, they underwent the same leap into modernity, the same emergence of symbolic thought that millennia later allowed Cro-Magnons to paint on cave walls.

A fox-tooth pendant is not a cave painting, as Baffier well knows, for she studies those paintings too. But it is a symbolic statement. "Oh, it's beautiful," she says quietly, turning the Neanderthal pendant in her fingers, peering at it over her glasses. "It's beautiful and it's moving. A 35,000-year-old bijou—isn't that moving?"

João Zilhão, director of the Portuguese Institute of Archeology, got the call from his wife and fellow archeologist, Cristina Araújo, while he was at a conference in Japan. She had heard from João Maurício and Pedro Souto, coworkers at a Neanderthal cave site. They had heard from a student named Pedro Ferreira, who had gone looking for rock art in the Lapedo Valley, about 90 miles north of Lisbon, and had found some small paintings.

Last November 28, Maurício and Souto went to the Lapedo Valley—which is really a small, steep ravine, a bit over a mile long and a stone's-throw wide. Olive groves and wildflowers, vegetable fields and villages sprawl up to the lip of the canyon, but its cool, lush depths are a world apart. The small stream at the bottom, the Caranguejeira, is hidden by reeds and bushes; the canyon walls themselves are practically hidden by a riot of diverse greenery.

Ferreira showed Maurício and Souto his rock art, and they confirmed that it looked man-made and old (Copper Age, it turned out). Then they looked across the ravine to the south side. Above the treetops they could see a limestone wall leaning out over the canyon. Prehistoric humans liked to take shelter under overhanging rocks like that. Maurício and Souto decided to have a look.

They found a mess, construction debris strewn along the base of the cliff, including an abandoned trailer, an old tractor hood, and a giant section of concrete drainpipe. In a fissure in the wall, just above eye level, Maurício and Souto saw sediments laced with stone tools, lots of animal bones, and black flecks of charcoal—the remains of Paleolithic campfires. But all along the wall they could also see the white gouge marks left by the teeth of a steam shovel. To build a road, the owner of the area had created a flat terrace where before there had been a tall slope of sediment—sediment that had washed off the top of the cliff and collected at the base over tens of millennia. He had used a steam shovel to dig the dirt from the cliff.

In retrospect the demolition man did archeology a big favor. Otherwise, what is now the base of the cliff at Lapedo would still be buried. Maurício saw a rabbit burrow disappearing under the rock. He reached his hand in and pulled out a radius and an ulna—the bones of a human forearm, though he wasn't sure of that at the time.

When the news reached Zilhão, he called Cidália Duarte, a physical anthropologist at the Portuguese Institute of Architectural Heritage. They and Araújo went up to Lapedo the next weekend. While Zilhão examined the stone tools embedded in the cliff face seven feet up, Maurício took the bone lady to the bones in the burrow. "I looked at them," Duarte recalls, "and I said, ëOoh—this is human! This is a kid!'" Meanwhile, Zilhão was looking at the stratigraphic sequence. He began to add it up: "If the kid is down there, and this up here is Solutrean . . . "

Solutrean is the third of four successive cultures—Aurignacian, Gravettian, Solutrean, Magdalenian—of the Upper Paleolithic or Late Stone Age. The Solutrean happened around 20,000 years ago. If the Lapedo Valley kid was seven feet below Solutrean sediments, that suggested he died thousands of years before the Solutrean. Zilhão looked at the bones: Theywere stained reddish with ochre. Red ochre is one of the things Upper Paleolithic moderns painted caves with, but they also buried their dead with it; the color seems to have had symbolic significance.

"So I immediately recognized that something big was there," says Zilhão. "The question was whether the bulldozing had completely destroyed the burial, and all we had to do was collect the fragments, or if something was still there intact."

The next day, Monday, they went back to their day jobs in Lisbon. The following Friday evening they were back at Lapedo, with Duarte and Araújo digging. "By Sunday evening we were really upset, because all we could find were bits and pieces, fragments of bone, and they didn't even have this reddish color," Duarte recalls. With night falling and spirits crumbling, they started tidying up the dig. Those final offhand brushstrokes did it: The red began to appear. Soon, as Araújo and Duarte gently swept away more dirt, they saw a patch of sediment as red as wine and as large as . . . a small child.

Now they faced a paleontological emergency: The skeleton was almost at the surface, exposed to the elements, which in this case included Boy Scouts. A troop had walked by during the weekend and regarded the diggers with ominous curiosity. That week Duarte signed up for an unscheduled vacation. Zilhão quietly abandoned his airy director's office and his paperwork at the archeological institute. "I just went away without telling anybody," he says, "so as not to run the risk of a leak."

They started digging in earnest. Right away they realized how lucky they had been: In removing tens of feet of dirt, the steam shovel had missed by just a few inches the body of the child. Unfortunately it had not missed the skull—Duarte could only find fragments of that. One of the first, though, was a beauty: the left half of the lower jaw, including teeth. It had a sharply pointed chin, which is just what you would expect from a Cro-Magnon; Neanderthals had weak chins.

The child was lying on its back, with its head and torso tilted a bit to its left, toward the cliff, and its right hand on its pelvis. Its right side was crushed, but the left side was intact. Ribs, vertebrae, pelvis, fingers, toes, the long bones of the arms and legs—all were there. Duarte and Araújo worked steadily through the Christmas holidays, hiding their work every night under the old tractor hood. Soon they had a new problem: up to 500 visitors a day. Zilhão's desire to keep the excavation secret had run into his desire to have it documented. He had asked Portuguese public television to videotape it, which the tv folk were happy to do—provided they could also run the story. On Christmas Day it opened the evening news: "A Child is Born."   On Christmas Day itself, Duarte was at the site alone. "I wasn't going to leave it there all exposed," she says. The work that day, on the rib cage, was particularly delicate. She was digging with a syringe, squirting acetone around the bones to dissolve the dirt—acetone evaporates quickly, so it doesn't soak the bone—and then removing it with a paintbrush and a plastic spoon. She was squatting, kneeling, and sometimes lying on her side next to the Kid. Earlier, near the clavicle, she had found a tiny seashell, covered with red ochre, with a minute hole. The Kid had worn it as a pendant.

At first Zilhão and Duarte guessed they had excavated a boy. The arms and legs looked robust. But then Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis, had a look at them. He decided the Kid was robust not because he was male, but because he had Neanderthal blood.

Trinkaus is a leading authority on both Neanderthal and early modern human anatomy. When the excavation started, Zilhão let him know right away. "João went out and got a digital camera and started e-mailing me images," Trinkaus says. He got excited too: While Upper Paleolithic skeletons in general are rare, there are no reasonably complete children's skeletons at all. Right after New Year's, while Duarte was still excavating, Trinkaus hopped a plane to Portugal.

He measured all the bones he could, especially the limbs—his specialty. In 1981, Trinkaus published a paper on limb evolution that is still cited. In it he documented a geographic pattern in people today: They get shorter the farther they are from the tropics and the closer they are to the poles. More precisely, their extremities get shorter. Inuits and Lapps have shorter forearms relative to their upper arms and shorter shinbones relative to their thighbones than do the Masai of East Africa. There is a simple explanation: Shorter, stockier bodies fare better in cold climates because they have less surface area to radiate heat. By measuring fossil limbs, Trinkaus showed that Neanderthals, denizens of ice age Europe, were hyperarctic—they had an even smaller shinbone-thighbone ratio than do Lapps. Early moderns from the Near East and Europe, on the other hand, were decidedly tropical in their legginess, like Africans today.

This was some of the earliest evidence for a theory of human origins that had not even been formulated then, but has since become orthodoxy. The out-of-Africa theory holds that humans today are descended from a small population of (long-legged) early moderns that walked out of Africa around 100,000 years ago. As they spread all over the world, they replaced whatever archaic humans they met, which in Europe were the Neanderthals. In this view, Neanderthals are a distinct population and maybe even a distinct species that went extinct at the hands of our ancestors, leaving no legacy at all.

Two years ago, when a team led by Svante Pääbo, now of the Max Planck Institute for Evolutionary Anthropology in Leipzig, isolated dna from a Neanderthal bone, many people thought the case had been clinched. The Neanderthal dna was different enough that there seemed to be no trace of it in modern dna; it suggested that Neanderthals and modern humans had evolved separately for half a million years and were unlikely to have interbred. Trinkaus was not moved: "There's a general impression that if something comes out of a million-dollar machine, then it's truth, whereas if something comes out of a bunch of dirty old bones that we clean with paintbrushes, then it's vague and ambiguous."

Based on his analysis of dirty bones from the Czech Republic and Croatia, Trinkaus has long favored a sort of watered-down out of Africa, in which the gene pool of modern humans migrating into Europe was seasoned by interbreeding with Neanderthals. The amount of interbreeding would have varied from place to place. One place Trinkaus didn't expect to see much, though, was on the Iberian peninsula, the last refuge of the Neanderthals.

Cro-Magnons reached northern Spain nearly 40,000 years ago, but for some reason they didn't spread south for another 10,000 years. By the time they crossed the Ebro frontier, as Zilhão has dubbed it after the large river in northern Spain, their kind had already executed striking cave paintings. South of the Ebro they encountered Neanderthals who were still making stone tools in the Middle Paleolithic fashion and not making ornaments at all. The better-armed modern invaders would have been almost as tall as the Masai and maybe as black; the indigenes would have been short and as pale as Lapps. It would be easy to picture the former simply wiping out the latter. But it is from this clash of cultures and anatomies, Trinkaus argues, that the Kid was born.

The sharp point of the Kid's chin screamed Cro-Magnon. So did the relatively small front teeth: Neanderthal front teeth were large compared with their molars. So did the red ochre burial style. And so, finally, did the radiocarbon date: At 24,500 years old, it was much younger than the last signs of Neanderthals.

But when Trinkaus measured the angle between the horizontal tooth line and the vertical line from the frontmost tooth down to the chin, the symphyseal angle, he got a clue that this was a strange Cro-Magnon. Instead of jutting forward of the teeth, the chin retreated a shade behind them. Cro-Magnon chins didn't do that, Trinkaus says, but Neanderthal chins did.

Even more significant, he thinks, are the limb proportions. Trinkaus measured the shinbone and the thighbone and found that the ratio fell way over at the Neanderthal end of the curve. He compared the circumference of the bones with their length, and found that the child had leg bones strong enough to support a stocky Neanderthal body. The limb proportions along with the receding chin are enough, Trinkaus says, to prove the child had Neanderthal ancestors as well as Cro-Magnon ones. "It only takes one feature," he says. "We've got two."

But many of his peers are skeptical. Arctic limb proportions don't prove a Neanderthal influence, some argue, since Lapps have them too; maybe the Kid was just an ordinary Cro-Magnon who had adapted to the ice age. And the mere fact that the skeleton is that of a child—whose features were still changing, and for whom no good Cro-Magnon comparisons exist—makes some researchers uneasy. "If an adult skeleton had been found, nice and complete, I'm sure we would still have fierce discussions," says Jean-Jacques Hublin of the French National Center for Scientific Research. "But interpreting the remains of a child, of which almost none of the skull is left—that's really a perilous exercise."

This summer, as the dig progresses, Duarte will be looking for more pieces of the child's skull. Finding its two front teeth would be nice (Neanderthals had big ones), or the occipital bone in the rear of the skull (it bulged out in Neanderthals), or even the tiny labyrinth of the inner ear. Hublin has used that feature, and that feature alone, to diagnose a Neanderthal bone at Arcy-sur-Cure.

Duarte also hopes to find the Kid's parents; Upper Paleolithic burials often come in groups. But Trinkaus does not expect she will find a Neanderthal mom and a Cro-Magnon dad. Zilhão's archeological evidence suggests the Kid was born at least two millennia after Neanderthals and Cro-Magnons first met in Portugal. The Kid, Trinkaus argues, must be the product of interbreeding over that entire period, not a one-time hybrid produced by star-crossed lovers. "This is not just two individuals who happened to meet in the bushes," he says.

There is likely to be fierce discussion about that conclusion too. The out-of-Africa model can readily tolerate a little hanky-panky between Neanderthals and Cro-Magnons. "In fact I expect it," says Hublin. A few hybrids wouldn't even disprove the view that Neanderthals were a different species. Animals of closely related species can sometimes interbreed, and sometimes the offspring are even fertile.

But if whole populations of Neanderthals and Cro-Magnons were blending, the notion that Neanderthals were replaced by immigrant moderns begins to lose meaning. To out-of-Africa proponents, such blending would conflict with the genetic and fossil evidence, and with the simple observation that people today look like Cro-Magnons and not like Neanderthals.To paleontologists who don't believe the out-of-Africa model, however—who think modern humans evolved all over the world from interbreeding populations of archaic humans including Neanderthals—Trinkaus's Lapedo kid is welcome news.

Trinkaus himself has never taken sides in this bitter debate. He sees it now moving onto his middle ground: A migration out of Africa happened, sure, but the migrants also interbred to varying degrees with the people they met along the way. Neanderthals are not us, but neither are they an evolutionary dead end—the Kid, if he is right, puts the truth in the middle. "Trinkaus is in the stratosphere," says Zilhão. "He has believed this for a long time. I couldn't care less—they could just as well be different species as far as I'm concerned. This just comes in handy."

It comes in handy as ammunition in a separate fight that is Zilhão's own. That debate concerns how smart Neanderthals were, and it is centered on the cave digs at Arcy. When French archeologists excavated there in the 1950s, they found dozens of animal-tooth pendants, bone tools, and 40 pounds of red ochre spread over the floor. At other sites, such artifacts have been attributed to modern humans. A few years ago, though, after Hublin ct-scanned a skull fragment found alongside the artifacts, and revealed the inner ear, he convinced most people that the bone was that of a Neanderthal, and so were the artifacts.

The conventional explanation is that the Neanderthal craftsmen at Arcy must have been imitating our ancestors. Modern humans were invading western Europe at around the time—35,000 to 45,000 years ago—when the Neanderthals were at Arcy. And whereas the few dozen ornaments found there are practically the only ones attributed to Neanderthals, thousands have been found at Cro-Magnon sites. Many researchers say it is common sense to assume that Neanderthals were "acculturated" by Cro-Magnons. Some even argue that the Neanderthals didn't really understand what they were doing: They copied such modern behaviors as wearing pendants, but they couldn't appreciate the symbolic meaning.

Lurking under all this is the question of why we survived and the Neanderthals didn't: Was it because their brains were inferior? That idea drives Zilhão up the wall. "What's involved here is not the wiring of the brain cells, it's the wiring of the brains into what we call culture," he says. "Forty thousand years ago, people couldn't read or write—are we saying they didn't have the intelligence?"

In a controversial paper published last year with Francesco d'Errico of the University of Bordeaux, and Dominique Baffier, Michèle Julien, and Jacques Pelegrin of the University of Paris, Zilhão tried to show that the Neanderthals were intelligent enough to make the Arcy artifacts—and thus the transition to Upper Paleolithic modernity—all by themselves. The Arcy Neanderthals, the researchers argued, made their tools and ornaments using techniques quite unlike those of the moderns—punching a clean hole through a fox tooth, for instance, whereas modern humans did a cruder job of gouging. Zilhão and d'Errico also claim to have proved, through a technical reanalysis of the highly uncertain dates attributed to nearly every relevant site in western Europe, that the Neanderthals couldn't have imitated Cro-Magnons—because they were acting modern thousands of years before any Cro-Magnons were around.

The Lapedo Valley kid drops into the murky waters of this debate like a cannonball. Some researchers say it makes no difference at all if the Kid is a hybrid. But if Trinkaus and Zilhão can prove that modern humans and Neanderthals mixed extensively in Portugal, it would surely affect our view of Neanderthals—by giving us an inkling of the view our ancestors held. Would they really have fraternized with beings who were too dim to understand the purpose of a necklace?

"If you have two populations of hunter-gatherers that are totally different species, that are doing things in very different ways, have different capabilities—they're not going to blend together," Trinkaus says. "They're going to remain separate. So the implication from Portugal is that when these people met, they viewed each other as people. One group may have looked a little funny to the other one—but beyond that they saw each other as human beings. And treated each other as such."
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