Most tadpoles begin metamorphosis in water but emerge onto land as they near adulthood. Two species of frog have terrestrial tadpoles that never enter water during metamorphosis.
Tadpoles are the larval form of frogs and toads. Frogs and toads are amphibians, meaning that they spend part of their time in water and part on land. Most species of frogs and toads lay their eggs in a water source, and tadpoles typically begin development in water. During metamorphosis, tadpoles lose their gills, develop lungs, gain legs and reabsorb their tails. Once legs begin to form and lungs replace gills, tadpoles move to land to complete metamorphosis. One frog species from India and a tropical bullfrog native to South America, however, both have tadpoles that are completely terrestrial.