Breathing is a gas exchange, taking in oxygen from the surroundings and letting out carbon dioxide.

All frogs start life as aquatic tadpoles, breathing underwater through internal gills and their skin. Then later most develop into land animals with lungs for breathing air. But in all stages breathing is controlled by pulsing the throat. Most frogs loose their gills when they metaorphise.

Frogs breath with their mouths closed. Their throat movements pulls air through the nostrils to the lungs. Then breathe out with body contractions.

The activity and temperature of an animal determine how important breathing is. Anurans have much more complex lungs then other amphibians, such as salamanders, because they're more active and have higher body temperature.

Lungs can also help in water. Filling the lungs with air gives a frog a better buoyancy, making it float more easily.

Frogs can also breath through their skin, with tiny blood vessels, capillaries, under the outer skin layers. The African 'Hairy' frog, Trichobatrachus robustus, has small lungs and during breeding seasons the males get hair like projections on their back legs. This is because of the high oxygen needs at this time.