A research team of the University of Cologne in Germany has published an open access paper arguing that a series of cold, dry phases during the last European ice-age triggered the demise and finally lead to the extinction of Neanderthals in Europe.
The oldest evidence of any hominids in Europe date back 700,000 to 600,000 years ago. At the time, Europe was covered in forests, with many large animals, like elephants, rhinoceroses, horses, deer and large bovines, roaming free. As prey species were abundant, different subspecies of the genus Homo coexisted contemporarily. From 350,000 to 40,000 years ago Neanderthals (H. neanderthalensis) were the dominant human species in Europe.
As during the ice-age, starting some 100,000 years ago, the climate cooled and Central Europe became inhospitable, they survived in refugial areas located along the southern borders of the European continent. In the next 60,000 years the climate oscillated between long, cold phases and short warm intervals. Pollen analysis shows that during the cold phases the forests, covering the continent during the warm intervals, were quickly replaced by an almost tree-free tundra.
Some 43,000 to 40,000 years ago sites with artifacts by Neanderthals disappear from the archaeological record, to be replaced by the culture of the Aurignacian, characterized by artifacts (like stone tools, prehistoric art and even musical instruments) attributed to the modern human species H. sapiens. Analyzing the annually deposited layers of stalagmites from two caves in modern Romania, the scientists were able to reconstruct the climate in Central and Eastern Europe between 44,000 and 40,000 years ago.
Chemical changes in the deposited layers suggest that the climate got more unstable and deteriorated, going from warm and humid to cold and dry. In response, as happened previously, the forests covering most of the continent were quickly replaced by a tree-free tundra. The last traces of Neanderthals are found before this cold phase. During the cold phase, any signs of human activity disappear completely. When the climate warms again new artifacts appear in the archaeological record, attributed to modern humans. The research argues that in the cold, dry tundra also large animals were rare. Neanderthals, a society of specialized hunters, would have faced a hard time to survive without large preys to hunt. Unlike previous cold phases, also this time the southern refugial areas were occupied by a new human species, as modern humans were migrating from the Near East into Europe. The already small populations of Neanderthals were forced to stay in the tundra and unable to hunt there large prey, they numbers quickly dwindled. Finally Neanderthals went extinct 40,000 years ago. The now empty landscape was quickly claimed by modern humans, migrating from the southern borders into the heart of Europe, as the climate became more hospitable again 40,000 to 35,000 years ago.