A Frog's Life
A Fish Out of Water
Some 365 million years ago, finned, aquatic animals evolved into tetrapods, the first four-legged vertebrates. Over time this new animal group moved onto land and gave rise to mammals, reptiles (including birds), and amphibians. Today frogs and other amphibians live in all but the harshest land environments, but many remain tied to water for development of their eggs and tadpoles.