Females joining hunt may explain Neanderthal Demise
By Colin Nickerson, Globe Staff | November 10, 2007
The Neanderthal extinction some 30,000 years ago remains one of the great riddles of evolution, with rival theories blaming everything from genocide committed by "real" humans to prehistoric climate change.
But a recent study introduces another explanation: Stone Age feminism. Among Neanderthals, hunting big beasts was women's work as well as men's, so it's a safe bet that female hunters got stomped, gored, and worse with appalling frequency. And a high casualty rate among fertile women - the vital "reproductive core" of a tiny population - could well have meant demographic disaster for a species already struggling to survive among monster bears, yellow-fanged hyenas, and cunning Homo
sapien newcomers.
A spate of recent discoveries has yielded intriguing clues about humanity's closest cousin. Neanderthals and humans split from a common ancestor some 500,000 years ago. Neanderthals had Europe to themselves until Homo sapiens started swarming out of Africa about 45,000 years ago - the beginning of the end for these archetypical cave dwellers, although they hung on for 15 millennia.
No other prehistoric people had quite the same kinship with humans: just 2,000 generations ago, the blink of an eye in evolutionary terms, Neanderthals walked among us and we among them. They might have been our lovers. Almost certainly they were our rivals, competing for the same giant elk and reindeer.
Then they were gone.
But these relatives are still rooted in our consciousness. Look at the Geico commercials, with the not-quite-human character taking offense at a car insurance company's offer of website access "so easy a caveman could do it." The gag, of course, is that Neanderthals are enough like humans to deserve respect - a sensitivity not many people would extend to more apelike members of the family tree.
"If Lucy were alive, we'd put her in a zoo," said Daniel E. Lieberman, professor of biological anthropology at Harvard University, using the nickname of a primitive hominid forebear who lived 3.2 million years ago.
"If a Neanderthal were to come along, we'd think he was kind of weird. But we might also wonder whether to admit him to Harvard," Lieberman said. "They remain this touchstone species that evokes strong emotions."
It's only in the past few years that scientists have reached broad consensus on what Neanderthals were - and weren't. "Neanderthals were a species of archaic humans that evolved in Europe separately" from modern humans, he said. "They were very much like us . . . But they weren't us."
Among the new findings:
# In addition to immense noses, elongated skulls, and barrel chests, some Neanderthals boasted flaming red hair, according to an international research team led by Harvard's Holger Roempler. This suggests they might have been pale-skinned, not the swarthy knuckle- draggers of the popular imagination. But they were still likely very hairy.
# Neanderthals possessed a gene known to underlie speech. The presence of the FOXP2 gene in two skeletons uncovered in the El Sidron cave in northern Spain suggests Neanderthals were capable of human-like language.
# The range of Neanderthals was much greater than scientists had previouslyimagined, extending to the heart of Asia.
Svante Paabo, head of genetics at Germany's Max Planck Institute for Evolutionary Biology, last month identified mitochondrial DNA taken from bones found in Siberia's Altay mountains as belonging to Neanderthals. The location lies 2,000 miles beyond what was previously regarded as the eastern limit of their territory. That find was a surprise because scientists have long thought that Asia of that era belonged solely to another archaic human species, Homo erectus.
"This puts Neanderthals on the doorstep to Mongolia and China," said Paabo. "So perhaps we will some day find evidence of a Neanderthal Marco Polo," who met and mingled with those vanished inhabitants of the Far East.
Meanwhile, Paabo is working on an audacious scheme to reconstruct the full Neanderthal genome from DNA recovered from fragments of bone. "This would be the first time that anyone has sequenced the entire genome of an extinct organism," he said.
On other fronts, scientists are searching for proof that Neanderthals and humans interbred. So far, there's no genetic evidence that these cousins, if they kissed, produced offspring.
"If they did do it, as everyone wonders, it didn't have an evolutionary effect," said Lieberman. "The question really says more about human's prurient interests."
Almost as provocatively, a husband-wife anthropological team has raised the possibility that female derring-do may have contributed to Neanderthals' demise.
The University of Arizona's Steven L. Kuhn and Mary C. Stiner, use archeological evidence to argue that Neanderthal females - unlike Homo sapien women of the Upper Paleolithic period - joined men in hunts at a time when stabbing giant beasts with a sharpish stone affixed to a stick represented the cutting edge of technology.
That's courageous, but probably bad practice for a population that never numbered much more than 10,000 individuals. The loss of a few males to a flailing hoof or slashing antler is no big deal, in the long run. But losing females of child-bearing age could bring doom to a hard-pressed species.
"All elements of [Neanderthal] society appear to have been involved in the main subsistence pursuit" of hunting large animals, Kuhn said. "There's not much evidence of classic female roles.
"Putting the reproductive core of the population - pregnant women, mothers of infants, children themselves - at such danger could have put Neanderthals as a whole at serious demographic disadvantage," he said.
Not only would women suffer casualties, Kuhn said, their full participation in the hunt would mean they were not harvesting wild
grains and other foods that could sustain their roving bands when game was scarce.
What finished off the Neanderthals is still bitterly disputed by paleoanthropologists and others in the field.
On one side are those who think Neanderthals were "culturally" overwhelmed by modern humans who just happened to possess better tools and weapons - throwing spears, for example, not jabbing spears - or adopted customs more appropriate for the Ice Age. From early days, human women appear to have sewed hide clothing, tended fires, and gathered vegetables rather than risking their lives on the hunt.
On the other side are those who believe modern humans were inherently superior, possessing "cognitive advantages" - read: more smarts - that made their ascent and Neanderthal decline inevitable. Cavefolk simply couldn't compete effectively with the more clever new kids on the block.
"Neanderthals were smart, sophisticated. They mastered fire. They made tools. But modern humans had selectively advantageous [genetic] traits that gave them an edge," said Richard G. Klein, a Stanford University paleoanthropologist. "Even tiny advantages in cognition, communication skills, and memory would have had huge downstream effects over time."
There are other plausible explanations for the Neanderthal extinction. Warming at the end of the Ice Age surely wasn't easy for robust people built for the cold. Or an epidemic could have so depopulated Neanderthal bands that the survivors couldn't replenish the species. A more sinister idea is that early humans wiped them out in a prehistoric genocide.
"On the other hand, humans and Neanderthals coexisted for thousands of years, so I think talk about genocide says more about how modern humans think," said Paabo. "What finally happened could be really boring. Maybe Neanderthals ran out of reindeer to hunt. So they dwindled and died. Species can disappear without us killing them."
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