The first ranid frogs were stuck in India for 60 million years according to Belgian researchers who have studied the frog's "molecular clocks". Although these frogs have since spread around the world, to the point where they constitute one-fifth of the world's amphibians, the frogs stayed in India because it was an island-and frogs cannot cross salt water, says Michel Milinkovitch a geneticist at the Free University of Brussels.
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