Tuesday, 17 February 2009

News of the Neanderthals

by Kathryn Hadley

The Neanderthals, who became extinct approximately 28,000 years ago, seem to be back in fashion! They have made the news at least three times over the past week. On Sunday February 7th, a recreation of their music was staged for the first time at the National Museum Cardiff. Results of recent research about their DNA and the cause of their extinction have been published over the last week: the Neanderthals may have been the victims of climate change and modern humans did not interbreed with the Neanderthals. We may not descend from them after all!

Last Friday, BBC News published an article reporting on the results of the latest research into the cause of the extinction of the Neanderthals, led by Professor Clive Finlayson, the director of the Gibraltar Museum, which suggested that climate change may have partly caused the death of the Neanderthals. In 2006, evidence from radiocarbon dates obtained from Neanderthal campfires in Gorham’s Cave, a natural shelter cut into the rock of Gibraltar, revealed that a small population of Neanderthals had survived, longer than was previously believed, in Spain, Portugal and Gibraltar. The discovery sparked further research and, according to Professor Finlayson’s latest conclusions, they may have lived until 24,000 years ago, almost 1,000 years later than previous estimates.

Nevertheless, even this small surviving population eventually became extinct. How and why? Previous research assigned a key role to the arrival of the Homo sapiens in the death of the Neanderthals. In the game of natural selection they were allegedly better equipped because they were more intelligent, had better technology and were more able to adapt. The latest research suggests, however, that the disappearance of the Neanderthals was an altogether more complex process which cannot be explained by one sole factor.

In his book The Humans Who Went Extinct, Finlayson notably explains how they disappeared at a time when sea surface temperatures were the coldest they had been for the previous 250,000 years. The phenomenon, known as the Heinrich Event 2, may have caused drought in Iberia, affecting supplies of food and water. The Heinrich Event 2 was part of a series of other Heinrich Events which may have affected the survival of Neanderthals in other parts of Europe.

In the words of Professor Chris Stringer, of London's Natural History Museum:
‘For many years, people assumed that it was an overall superiority of modern
humans: that modern humans were more intelligent, that they had better
technology, or had more effective adaptations. They thought that when they came
into Neanderthal regions, the Neanderthals very quickly disappeared, because
they were out-competed. What we've learnt recently, is that the story was much
more complicated. There probably wasn't a single cause of the Neanderthal
extinction. They may have died out in different places for different

Finlayson’s conclusions are, however, not unanimous. Chronis Tzedakis, a professor at the University of Leeds, has notably argued against Finlayson that the Neanderthals survived climate change. His research has sought to put archaeological evidence for the survival of the Neanderthals in its climatic context. Results have revealed, however, that radiocarbon dates and calendar dates do not always match up, leading to discrepancies that can be thousands of years apart. He notably discovered that evidence from Gorham’s Cave followed the Heinrich Events, thus suggesting that the Neanderthals must have survived the Heinrich Event 2.

In Tzedakis words:
‘What we have managed to show is, in a sense to simplify the equation, and I
think we can be reasonably certain it was not the effects of abrupt,
catastrophic climate change and Heinrich Events that were responsible. Now, that
does not mean that climate was not involved at all. It is entirely possible that
you had a combination of factors, perhaps competition from modern humans at a
time of limited resources. Because climate is deteriorating at that time - we
are moving into the glacial maximum. So resources are scarce; but, on the other
hand, climate alone is not the most parsimonious explanation. So I think the
jury is still out on the factors that may have been involved.’

Although, both scientists agree that the Heinrich Event 2 took place, whether or not it caused the death of the Neanderthals is still open to debate and remains an unsolved mystery. Finlayson’s last words seem, however, particularly appropriate: over focusing on the cause of their extinction, risks causing us to overlook the fact that the Neanderthals nevertheless survived for three or four thousand years.
‘As far as I see it, they are intelligent human beings. Different, but when has
difference meant superiority or inferiority? That's the take-home message I
would have about our understanding of the Neanderthals today. A parallel form of
being human. "It is quite sobering that at one point in the history of the
planet, there were different types of us of which one - possibly by chance -
survived. In other words, we might be the Neanderthals discussing this today.’

Part 3 of the Neanderthal story will follow tomorrow, with the latest results of genetic research! What evidence is there that modern human beings descend from the Neanderthals?

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