Neanderthal and CroMagnon skulls. The Neanderthal skull (left) was found at La Ferrassie, France, in 1909, and is thought to be around 70,000 years old. The other skull is CroMagnon 1, found as Les Eyzies, France, in 1868, and dated to 30,000 years ago. Neanderthals and CroMagnons cohabited in Europe between about 40,000 and 3025,000 years ago, when the former died out. Neanderthals had occupied the region from as far back as 350,000 years ago. CroMagnons were anatomically similar to modern humans, and are their ancestors. It is not known for sure what caused the extinction of the Neanderthals, but competition with the advanced CroMagnons is unlikely to have helped their cause.