Like humans use aeroplanes for flying, snails may have ridden over shorebirds or stuck to their legs to cross Central America twice in the past million years, said scientists.
"Just as people use airplanes to fly overseas, marine snails may have used birds to fly over land," said Mark Torchin, a staff scientist at the Smithsonian Tropical Research Institute.
The idea goes back to Charles Darwin, who speculated that migratory birds could transport snails to distant places.
Sometimes such events trigger devastating biological invasions -- introducing new diseases, wiping out resident species or causing economic damage to food crops, according to a Smithsonian statement.
"There's also a big difference between one or two individuals ending up in a new place, and a really successful invasion, in which several animals survive, reproduce and establish new populations," added Torchin, the journal Proceedings of the Royal Society: B reports.
"Not only snails, but many...organisms may be able to 'fly' with birds," said study co-author Osamu Miura, assistant professor at Japan's Kochi University and former post-doctoral fellow at the Smithsonian Institute.
In 1940, George Gaylord Simpson, who studied natural history recorded in fossils, coined the term "sweepstakes dispersal" to describe the unlikely events in which animals cross over a barrier resulting in major consequences for diversity of life.
taken from http://www.phenomenica.com/2011/09/snails-rode-over-birds-to-cross.html
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