Humans could settle in the middle latitude only lately at the scale of hominid evolution. In Western Eurasia, the Neandertals raised at the margin of the hominid eco-geographic domain. Geographic and climatic conditions seem to have played a major role in the segregation and evolution of the group. Eventually, the replacement of the Neandertals by Modern invaders can also be analysed at the light of environmental and paleodemographic changes. A spectacular paleontological record and the still scarce paleogenetical data will allow to test whether the evolutionary pattern of this group partly results from one or several bottle-neckings.