A common garden snail from the south of France, which missed Britain on its way to Ireland, could provide proof that humans migrated from southern Europe to Ireland 8,000 years ago.
Geneticists from the University of Nottingham have shown that the Cepaea nemoralis snail, found in Ireland and the Pyrenees, are genetically almost identical, despite living thousands of miles apart.
Dr Angus Davison, Reader in Evolutionary Genetics at the University, said: “There is a very clear pattern, which is difficult to explain except by involving humans.
“If the snails naturally colonised 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.”
Records show that Mesolithic or Stone Age humans would eat snails or even farm them.
Humans may have taken the slimy creatures on an ancient trade route from a river that flanks the Pyranees – around northern Spain and southern France – to the Atlantic, either accidentally or as food, as humans migrated from the South of France to Ireland 8,000 years ago.
Despite sharing a close geographical proximity, Ireland is home to a number plants and animals not found in Britain.
“You would think that anything that gets to Ireland would go through Britain, but it has been a longstanding mystery as to why Ireland is so different from Britain.
“For these snails, at least, the difference may be that they hitched a ride on a passing boat,” added Dr Davison.