Amphibians lay their eggs in water, and young amphibians tend to resemble small fish. The tadpole, or newborn frog, is born and lives in water. It has a tail that allows it to swim like a fish. It also has gills so that it can breathe under water. As the tadpole grows into a frog, it loses its gills and tail, and develops legs for moving on land. Most amphibians can both walk and swim in water. Depending on the species of amphibian, breathing can take place in gills, lungs, the lining of the mouth, the skin, or some combination of these. In Amphibians body temperature changes with its environment. In cold climates, amphibians hibernate during the winter.