The Neanderthals of southwestern Europe may have gone extinct approximately 40,000 years ago because, in large measure, they were simply overwhelmed by the rising numbers of modern humans around them. It is an old and simple hypothesis that, until now, had not been backed up with an extensive statistical evidence.
     The study involved analysing the density of Neanderthal and early modern human artefacts and occupation sites across the Dordogne region in southwestern France, an area well-known for the highest concentrations of Middle Palaeolithic (300,000 to 30,000 years BCE) to Upper Palaeolithic (50,000 to 10,000 years BCE) periods of human occupation.
     Focusing on the transition period of 55,000 to 35,000 BCE, researchers analysed evidence of three successive distinct stone tool industries: the Mousterian-of-Acheulian (55,000 to 44,000 BCE) and Chátelperronian (44,400 to 40,250 BCE) - generally associated with the Neanderthals - and the Aurignacian (40,250 to 35,000 BCE), largely identified as that of the modern humans. The study also included an examination and analysis of the animal food remains at the sites.
     The evaluation suggests an increase in overall population densities across the transition by a factor of about 9 to 10, in favour of the modern human.
     Faced with this kind of competition, the Neanderthals seem to have retreated initially into more marginal and less attractive regions of the continent and eventually - within a space of at most a few thousand years -  declined to extinction.

Edited from Popular Archaeology (26 July 2011), EurekAlert! (28 July 2011)