Tadpoles breathe through the gills by moving their throat through regular rhythmic movements, known as pulsing. They can also breathe through lungs, according to Natural History. When they metamorphose into frogs, they eventually lose their gills and start breathing through the lungs or through the skin.
Tadpoles are aquatic creatures and can only breathe and survive in water. The tiny external gills on tadpoles help to draw oxygen from water by means of thin membranes called lamellae.
Occasionally, tadpoles may rise above the water surface and gulp oxygen from the air. As they grow, they go through various changes, including growing and losing tails. Adult frogs breathe through the lungs; however, like tadpoles, breathing is controlled through throat movements.
A frog breathes with its mouth closed. The pulsing throat movements pull air into the lungs through the nostrils before it is forced out by the frog’s body contractions. Although frogs use their lungs primarily for breathing on land, they can also use them in water to float easily. When the lungs are filled with air, a frog gets better buoyancy so that it floats more easily. In addition, the outer layers of a frog’s skin are lined with capillaries and blood vessels that aid in breathing.