Snails of the genus Balea perversa make long trips glued to the legs of the birds. Although these snails developed in Europe, they have found their relatives elsewhere in the world.
Balea pervers has been found far from Europe. At a distance, in the Azores islands. On the island of Tristán da Cunha, the genus has been divided into eight species. This means that the snail arrived on the island long ago, long before the man arrived there. The hypothesis of the transport of snails on board the ships has been discarded, so it has taken force the hypothesis that the birds have made vector. In fact, the snails of the perverse Balea species have an atypical and sticky slime that allows them to stick to the legs of the birds.
This new hypothesis would also explain how snails have traveled from Europe to Azores and, again, to Europe. Researchers have reached this conclusion by analyzing the DNA of the mitochondria of snails.
These travelling snails do long distances without a doubt, considering that they have only one leg. Some plants, for long distances, use water currents, wind or other animals, something less common in the animal kingdom.