Frogs have a three-stage life cycle, too: egg, larva, and adult.
The mother frog deposits her eggs in a pond or other wet environment. When the eggs hatch, tiny larvae (tadpoles) emerge. Tadpoles, of course, are aquatic—they have gills and long tails, and they swim around like fish. But toward the end of the tadpole phase, changes happen: Legs and lungs begin to form, the tadpole’s tail shrinks, and its mouth widens. When metamorphosis is complete, the adult frog is so changed that it hops out of the water and lives on land from then on. Once legless, its legs are now so powerful that they make up one-quarter of the frog’s body mass. Some frogs can leap 10 to 20 times their body length.
