Strong bones, and thus dim-witted? – neanderthals versus homo sapiens; includes a related article on the similarity of neanderthals and homo sapiens; The Top 100 Science Stories of 1996
Tim Folger
Why did Neanderthals disappear some 30,000 years ago, while Homo sapiens continued to thrive? At a paleontology conference last April, anthropologists Erik Trinkaus and Chris Ruff announced they had found some clues: the Neanderthals had stronger arms and they ran their children ragged.
The two anthropologists studied about two dozen fossil skeletons of Neanderthals and early modern humans, all from well-excavated sites in the Neanderthals East – the oldest dating from 150,000 years ago – where both populations lived at various times. Although anthropologists aren’t sure whether the two peoples ever overlapped, they clearly had much in common, says Trinkaus, who works at the University, of New Mexico. “In the Near East both humans and Neanderthals are found with archeological material that is, except in subtle details, indistinguishable he says. “They made the same type of tools, they hunted the same type of animals, they lived in very similar places.”
Why then did one group vanish and the other prosper? The answer, says Trinkaus, may be found in their bones. He and Ruff, who teaches at Johns Hopkins, used X-rays and computer models of the fossils to study the stresses the bones were subjected to during life. They found that Neanderthal bones consistently seem to reflect more vigorous activity. The most likely explanation, says Trinkaus, given that both populations used essentially the same tools in the same environment, is that Neanderthals used their tools less efficiently. The extra effort put additional loads on the bones, which, as weight lifters know, strengthens them.
Using a computer program designed for orthopedic research, Ruff and Trinkaus measured the cross-sectional structure of the bones, a basic indicator of strength. They then factored in the Neanderthals’ and humans’ different proportions, to allow for the former’s greater weight and overall robustness. Finally they compared the relative strength if arm and leg bones from the two groups.
The strength of the leg bones of Neanderthals and early modern humans turned out to be equal. But the upper arm bones of Neanderthals were significantly stronger than those in humans. This means, Trinkaus thinks, that humans probably chose food that was easier to process or they used their tools more intelligently and less laboriously. One of the keys to evolutionary success, says Trinkaus, is the efficient use of energy. The more efficient a people, the better their chances of surviving. “It takes only a very subtle difference in life-style to make a big difference in terms of evolutionary success,” he says.
This work complemented earlier research by Trinkaus on differences in Neanderthal and human hipbones, particularly in the knobby neck of the femur, or thighbone, which fits into the hip socket. Modern studies have shown that this neck tends to get bent in active children. In Neanderthals, Trinkaus found, it was much more sharply bent than it was in humans. He interprets this to mean that Neanderthal children had to accompany adults on foraging trips, while human children remained at camp with other adults. Such a social structure may have given early human children a better chance of survival.
Critics say, Ruff and Trinkaus may not be justified in inferring so much about behavior from skeletons. But Trinkaus says his work fits other evidence that early humans simply outcompeted Neanderthals for resources. “We can say from the fossils that these populations were using their bodies in very different ways to manipulate their environment.”
RELATED ARTICLE: OR MUCH LIKE US?
If Neanderthals were brutishly inefficient tool users, would you expect them to have played the flute? Evidence that they may have done just that turned up in 1996 in a cave in Slovenia. in one of the most surprising archeological finds in years, Ivan Turk, an archeologist at the Slovenian Academy of Sciences, uncovered what appears to be a small flute made from the thighbone of a cave bear. Four precisely aligned holes puncture one side of the four-inch-long bone; two of the holes are intact, two had been damaged.
If it is indeed a flute, it’s by far the oldest musical instrument ever found, and the first to be attributed to Neanderthals. Turk found it buried with stone tools characteristic of those used by Neanderthals, just below a hard-packed, cementlike deposit that would have prevented it from settling down from more recent sediments. Bonnie Blackwell, a geologist at Queens College in New York, dated the flute with a technique called electron spin resonance. She says it dates from 82,000 to 43,000 years ago, a time when Neanderthals – but no anatomically modern humans – inhabited Europe.
“It looks very similar to the bird bone flutes of much later periods,” Blackwell says, “and it drastically changes our opinions of Neanderthals. The recognition that they may have had music suggests they probably had fairly well-developed speech. They certainly did a lot more than just sit around the cave and bash tools.”
But when they did bash tools they often bashed sophisticated ones. Last March archeologist Eric Bolida reported the discovery, at an open-air site in Syria, of several stone tools that were more than mere stone: on one side, away from the cutting edge, they bore traces of a black substance. Chemical analysis showed it was bitumen – a thick, sticky material used today in roofing tar – and that it had been heated to a high temperature, which would have made it liquid and supple. Boeda, who works at the University of Paris X in Nanterre, thinks the bitumen was a glue that held handles on the tools. Before his find, the oldest known use of bitumen as an adhesive had been a 10,00-year-old sikcle from Syria, but Boeda’s tools date back at least 42,500 years. In September he found a Neanderthal skull at his site, in sediments from the same period as the tools. He’s fairly certain the toolmakers were Neanderthals. “I think the Paleolithic period was a time when a great number of technological and symbolic innovations arose,” he says.
Another find announced last January may support that view. in a cave in southern France, near Bruniquel, a team of archeologists led by Frangois Rouzaud of the Regional Archeological Service in Toulouse discovered the foundation of a structure whose purpose remains mysterious. Made from broken stalactites and stalagmites, the foundation measures about 13 feet by 16 feet. Based on radioactive dating of a burned bear bone found in the cave, the structure may be as much as 47,000 years old. That would place it firmly within Europe’s Neanderthal era. Whatever the structure was, it wasn’t a sheiter – and it may not have served a utilitarian purpose at all. “In the cave, you’re not going to be hit by rain,” says Randall White, an archeologist at New York University familiar with the Bruniquel discovery. “The chance of it being a protective shelter seems pretty remote. So what is it? Is this evidence for some kind of, for lack of a better word, ritual activity?”
Flutists, makers of sophisticated tools, people perhaps of higher purpose – this past year’s discoveries have helped put human flesh on the elusive Neanderthals. “The larger debate is about whether they were our intellectual equals or were somehow neurologically different from us,” says White. “The more this kind of evidence accumulates, the more they look like us.”
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