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Competition, not climate, killed Neanderthals: study

Dec. 29, 2008
Courtesy PLoS One
and World Science staff

Ne­an­der­thal peo­ple died off mainly be­cause they lost in a com­pe­ti­tion for re­sources with the an­ces­tors of mod­ern hu­mans—not be­cause of cli­mate change, re­search­ers say in a new stu­dy.

How­ev­er, cul­tur­al ex­change and even in­ter­breed­ing be­tween the two groups could have al­so oc­curred as they in­ter­acted, the sci­en­tists add.

Ar­chae­o­lo­gists have long de­bat­ed the rea­sons for the dis­ap­pear­ance of the Ne­an­der­thals, the stocky breed of early hu­mans who oc­cu­pied Eu­rope be­fore the ar­ri­val of hu­man popula­t­ions like us around 40,000 years ago.

The re­search­ers in the new study re­con­struct­ed cli­mat­ic con­di­tions dur­ing the times that fol­lowed, and an­a­lyzed the dis­tri­bu­tion of sites as­so­ci­at­ed with Ne­an­der­thal and mod­ern hu­man popula­t­ions.

The in­ves­ti­ga­tors used an ap­proach typ­ic­ally used to study the im­pact of cli­mate change on bio­divers­ity. This math­e­mat­i­cal meth­od, they said, al­lowed them to find out wheth­er the ecolog­i­cal niche ex­ploited by a popula­t­ion grew, shrunk or stayed un­changed dur­ing a par­tic­u­lar per­i­od. 

Com­par­ing these re­con­struct­ed ar­eas for Ne­an­der­thals and an­a­tom­ic­ally mod­ern hu­mans dur­ing each of sev­er­al cli­mat­ic phases, the re­search­ers con­clud­ed that Ne­an­der­thals could have main­tained their range dur­ing a per­i­od of rel­a­tively mild cli­mate called Green­land In­ter­sta­di­al 8. 

But in­stead, they wrote, the ar­chae­o­log­i­cal rec­ord shows Ne­an­der­thal popula­t­ions with­er­ing away dur­ing this per­i­od, while mod­ern hu­mans ex­pand­ed from North to South.The last Ne­an­der­thal popula­t­ions are be­lieved to have hung on in south­ern Spain, where they van­ished by an es­ti­mat­ed 24,000 years ago.

The re­search­ers, led by Wil­liam E. Banks of the Na­tional Sci­en­tif­ic Re­search Cen­ter in France, re­ported their find­ings in the on­line re­search jour­nal PLoS One Dec. 24.

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Neanderthal people died off mainly because they lost in a competition for resources with the ancestors of modern humans—not because of climate change, researchers say in a new study. However, cultural exchange and even interbreeding between the two groups could have also occurred as they interacted, the scientists add. Archaeologists have long debated the reasons for the disappearance of the Neanderthals, the stocky breed of early humans who occupied Europe before the arrival of human populations like us around 40,000 years ago. The researchers in the new study reconstructed climate during this period and analyzed the distribution of archaeological sites associated with the last Neanderthals and the first modern human populations. The investigators used an approach typically used to study the impact of climate change on biodiversity. This mathematical method, they said, allowed them to find out whether the ecological niche exploited by a population grew, shrunk or stayed unchanged during a particular period. Comparing these reconstructed areas for Neanderthals and anatomically modern humans during each of several climatic phases, the researchers concluded that Neanderthals could have maintained their range during a period of relatively mild climate called Greenland Interstadial 8. But instead, they wrote, the archaeological record shows Neanderthal populations withering away during this period, while modern humans expanded from North to South.The last Neanderthal populations are believed to have hung on in southern Spain, where they vanished by an estimated 24,000 years ago. The researchers, led by William E. Banks of the National Scientific Research Center in France, reported their findings in the online research journal PLoS One Dec. 24.