Neanderthal and Climate Change
The last Neanderthals in Europe died out at least 37,000 years ago â€“ and both climate change and interaction with modern humans could be involved in their demise. The Neanderthal is an extinct member of the Homo genus that is known from Pleistocene specimens found in Europe and parts of western and central Asia. Neanderthals are either classified as a subspecies of humans or as a separate species. How and why they died out is a matter of debate.
Professor JoÃ£o ZilhÃ£o and colleagues proposed 20 years ago that, south of the Cantabro-Pyrenean mountain chain, Neanderthals survived for several millennia after being replaced or assimilated by anatomically modern humans everywhere else in Europe.
Although the reality of this Ebro Frontier pattern has gained wide acceptance, two important aspects of the model have remained the object of unresolved controversy: the exact duration of the frontier; and the causes underlying the eventual disappearance of those Neanderthal populations (ecology and climate, or competition with modern human immigrants).
Professor ZilhÃ£o and colleagues now report new dating evidence for an archaeological culture unquestionably associated with modern humans. This constrains the age of the last Neanderthals of southern and western Iberia to no younger than some 37,000 years ago.
Climate change, we're told, poses the single gravest threat to the survival of our species. This may have been one of the causes of the demise of the Neanderthal. Some evidence had suggested that they had survived in what is now called Spain or Iberia longer than other lands.
The evidence from the Zilhao study puts at five millennia the duration of the Iberian Neanderthal, and counters speculations that Neanderthal populations could have remained in the Gibraltar area until 28,000 years ago.
Neanderthals had many adaptations to a cold climate: short, robust builds, and rather large noses which are common species.traits selected by evolution in cold climates. Their cranial capacity was larger than modern humans, indicating that their brains may have been larger.
Professor ZilhÃ£o in his study (Dating the Emergence of Anatomical Modernity in Westernmost Eurasia) states: â€œI believe the â€˜Ebro frontierâ€™ pattern was generated by both climatic and demographic factors, as it coincides with a period of globally milder climate during which oak and pine woodlands expanded significantly along the west faÃ§ade of Iberia.
â€œPopulation decrease and a breakup of interaction networks probably occurred as a result of the expansion of such tree covered landscapes, favoring the creation and persistence of population refugia.
â€œThen, as environments opened up again for large herbivore herds and their hunters as a result of the return to colder conditions, interaction and movement across the previous boundary must have ensued, and the last of the Neanderthals underwent the same processes of assimilation or replacement that underpin their demise elsewhere in Europe five millennia earlier.â€
Whatever happened to the last Neanderthals may never be clearly known. Climate change with its changes in ecosystems would have had an impact.
For further information: http://www.bristol.ac.uk/news/2010/6801.html