You might find the identical cousin of this Irish banded wood snail in the forests of faraway France. Despite living thousands of kilometres apart, their stripy shells and DNA are so similar that they offer a clue to ancient human migrations.
Banded wood snails from Ireland and the Pyrenees of Spain and southern France share shell patterns and mitochondrial genes that are rarely seen elsewhere in Europe. Angus Davison and colleagues from the University of Nottingham in the UK think that's because people carried them across the Atlantic on a Stone Age voyage.
"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," says Davison.
There are records of Mesolithic humans eating snails in the Pyrenees, and perhaps even farming them, he adds. They could have travelled from France to Ireland via the river Garonne, an ancient trade route to the Atlantic.