New genetic evidence suggests amphibians migrated from North America to Asia via a land bridge connecting Alaska and Siberia about 80 million years ago.

It explains how colonies of lungless salamanders, which breathe through their skin, wound up in Italy and Korea when 98 percent of the species live in the Western Hemisphere.

Researchers from the University of California, Berkeley, and Seoul National University concluded the family originated in North America 180 million years ago, when dinosaurs roamed. As global temperatures rose 100 million years later, they went north. Over 10 to 15 million years, they made it to what is now the Bering Sea and into eastern Asia, and then to Europe.

The migration is impressive considering that a typical salamander never strays outside a 250 to 300 square foot area, said David Vieites, lead author of the analysis in Proceedings of the National Academy of Sciences. "They are in the size of a room basically their whole life."