Very recently there has been some very exciting news about the fate of the Neanderthals. Seems about 4% of the Human Genome is made up of Neanderthal genes. This means that in the past modern Humans also called Homo sapiens, or sometimes Cro-Magnon Man, interbreed with Neanderthals and produced fertile offspring. Since different species generally may breed but not produce fertile offspring, this means that Neanderthals should now not be consider a separate species at all.
However this interbreeding does not explain what happened to the Neanderthals as a group. The Neanderthals as a species went extinct about 30,000 years ago after having thrived some 300 hundred thousand years in Europe. There are many ideas, often called the Neanderthal extinction hypotheses, which try and answer that very question. Early Modern Humans, moved out of Africa and entered the Neanderthal’ range about 80 to 90 thousand years ago. The two species coexisted for some for some 50,000 years before the Neanderthals finally disappeared completely.
Even before the recent discovery interbreeding had been one of the hypotheses; many scientists thought that Neanderthals were a sub-species of humans and that they could have interbred with modern humans. This is now apparently proved true.
But interbreeding is not the only theory as to the ultimate fate of the Neanderthals.
The Rapid Extinction theory states that the relatively short duration of overlap between the two human species supports a “rapid extinction” scenario. Biologist and writer Jared Diamond puts forward the idea of clash between the two species that the Neanderthals ultimately lost. Diamond also hypothesizes that a disease could have transferred from Modern Humans to Neanderthals and the Neanderthals succumbed because they had no natural immunity to this new infection.
Another the next theory is that Modern Humans had some kind competitive advantage over Neanderthals when it came to hunting and reproduction, such as a clear division of labor between men and women. Some studies show that Modern Humans had better weapons with which to hunt. Seems the Cro-Magnons had enhanced hunting ability and were better fed. One study shows that if Homo sapiens had just one more child per couple that survived to reproduce that that alone would overwhelm the Neanderthal population.
In 2009 an anthropologist announced that it that at least in one case a Neanderthals was killed and eaten by Cro-Magnons and then the teeth was worn as a necklace. This is based on the discovery of a single Neanderthal jawbone that seems to have been cut and skinned like food and its teeth had been manually removed.
Of course it could have been any one or more than one of these theories that could have caused the final extinction of the Neanderthals.
Jared Diamond, The Third Chimpanzee: The Evolution and Future of the Human Animal, Harper Perennial, 2001.