Neanderthals: Done in by Competition, Not Climate

Jan. 8, 2009 -- Climate change has become the default scapegoat for nearly every extinction on Earth lately. But a new study lets climate off the hook for at least one dramatic event: The disappearance of the Neanderthals from Europe about 35,000 years ago.

Scientists have long debated what caused the demise of this human-like species. One camp argues that the Neanderthals fell victim to a dramatic cooling of the environment. The other view holds that prehistoric humans squeezed the Neanderthals out.

"There have been dozens and dozens of articles on one side or the other," said William Banks, an archaeologist at the French Centre National de la Recherche Scientifique in Bordeaux.

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The study borrowed a tool from biodiversity research. Called "ecological niche modeling," the technique begins with a look at where a particular species lives. From each region, scientists compile details about geography, climate, and other environmental conditions.

Then, a computer model predicts where else that same suite of conditions exists. The results indicate the species' geographical range and also suggest how that range might expand or contract with environmental changes.

Banks and colleagues applied a version of this technique to ancient human species. They used a database to gather information from about 1,300 archaeological sites around Europe, dating back to three time periods: before, during, and after a massive cooling event about 40,000 years ago.

During that period, called Heinrich Event 4, Europe succumbed to cold, dry weather. Icebergs descended from the Arctic all the way down to Spain. Soon after, nearly all evidence of Neanderthals disappeared from the archaeological record.