Neandertal debate goes south.

Neandertals lived on southwestern Europe's Iberian coast until about 24,000 years ago, sharing the area for several thousand years with modern humans before dying out. This new finding indicates that Neandertal extinction occurred surprisingly gradually, at least near the Mediterranean Sea, says a team led by Clive Finlayson of the Gibraltar Museum.

In contrast, many other researchers suspect that Neandertals hit an evolutionary dead end 30,000 years ago, succumbing to competition from Homo sapiens who arrived in western Europe 32,000 years ago.

Between 1999 and 2005, Finlayson and his colleagues excavated Gorham's Cave in Gibraltar, located at Spain's southern tip. Radiocarbon dates for pieces of burned wood retrieved among Neandertal stone tools indicate that these human ancestors used part of the cave from 32,000 to 24,000 years ago, the investigators report in a paper published online Sept. 6 for an upcoming Nature.

New radiocarbon evidence from other cave sediments, which yielded artifacts typical of modern humans, places H. sapiens in the cave starting 19,000 years ago, although they were in the area far earlier. Small groups of Neandertals and modern humans simultaneously inhabited Gibraltar and nearby locales for several millennia but had little contact with each other, the researchers theorize.

Some archaeologists disagree. Because tiny amounts of soil contamination can markedly reduce radiocarbon ages, Finlayson probably overestimated how long Neandertals stayed in Gibraltar, remarks Francesco d'Errico of the University of Bordeaux in France.

H. sapiens material previously excavated from another part of Gorham's Cave dates to 30,000 to 28,000 years ago, a sign that Neandertals and modern humans mingled there, contends Joao Zilhao of the University of Bristol in England.--B.B.