In the 1990s, the remains of six Neanderthals -- two adults, two adolescents and two children -- were found in a small cave at Baume Moula-Guercy in the Rhône valley in southern France. The bones bear many of the hallmarks of cannibalism: cut marks made by stone tools, complete dismemberment of the individuals, and finger bones that look as if they've been gnawed by Neanderthal teeth, rather than by other carnivores. Remains from other sites in Croatia, Spain and Belgium also show evidence of cannibalism. But in each case, there has been a lack of evidence to answer the question...