Science News: Improved radiocarbon techniques suggest that Neanderthal cave sites may be at least 10 000 years older than earlier studies have indicated. If so, scientists may also have to revise their understanding of how and why the early hominids vanished. In a paper published online yesterday in the Proceedings of the National Academy of Sciences, Rachel Wood of the Australian National University in Canberra and colleagues explain that the organic material on which radiocarbon dating depends can become contaminated with modern material. To remove possible impurities, Wood’s team used new ultrafiltration methods to reassess bones and other artifacts found on the Iberian Peninsula, the last known region the Neanderthals inhabited. However, the number of specimens that Wood’s team was able to test was severely limited because ultrafiltration relies on well-preserved fossils, which are rare in warm climates such as those of Spain and Gibraltar.