The overlap figure shrank in February with new research by Paul Mellars of Cambridge University based on improved carbon-14 dating to show that modern humans started encroaching from Israel upon Neanderthal territory in the Balkans 3,000 years sooner than previously thought. This rate suggests Neanderthals succumbed sooner to big climate shifts or competition from modern humans for resources and that they might have overlapped for only 1,000 years at sites in western France.
Try zero years, says anthropologist John Hawks of the University of Wisconsin-Madison.
There is no longer any biological evidence of overlap between Neanderthals and non-Neanderthals in Europe, Hawks wrote recently in his blog. Many anthropologists are aware of this but "would like to sweep it under a rug," Hawks told LiveScience.
See also the interesting timeline of human evolution in the article.