NOTTINGHAM, ENGLAND—Geneticists have found that a subpopulation of the wooded band snail in Ireland is closely related to another lineage of the species living in the Pyrenees in southern France. Previous studies used radiocarbon dating to show that the snails, which have a white lip on their shells, first arrived in Ireland around 8,000 years ago. There are no similar populations between southern France and Ireland, leading scholars to believe that the snails traveled with humans migrating from the Pyrenees to Ireland. "There is a very clear pattern, which is difficult to explain except by involving humans," explains the University of Nottingham's Angus Davison. "If the snails naturally colonized Ireland, you would expect to find some of the same genetic type in other areas of Europe, especially Britain. We just don't find them." The snails could have been caught up in the ancient migration because they were an important food supply, or perhaps they were carried unintentionally in fodder for animals.