How Do Frogs Breathe under Water?
Under water, frogs breathe through their skins. A frog is an amphibian. That is to say it lives both on land and in water. It has lungs, but it has no ribs and therefore cannot expand its chest and suck air into its lungs as do reptiles, birds and mammals.
Frogs breathe with their mouths closed and the throat sack pulls air through the nose and into their lungs. Their throat movements pull air through the nostrils and back into the lungs, and then they breathe out with their bodies contracting.
On land air is drawn in and out of the frog’s nostrils, which have valves in them, by pulsations of the floor of the mouth. The air is forced in and out of the lungs by contractions of the throat and body muscles. A frog’s mouth is always kept tightly closed and the pulsations of the throat vary from 120-140 a minute.
Frogs nostrils are placed on top of their head so that they are able to breathe at the same time that they are in the water so that they can always be on guard.
Breathing is a gas exchange that takes oxygen from the surroundings and lets out carbon dioxide. The frog’s lungs are not only useful for breathing on land, but are also helpful when the frog is in the water. This is because filling the lungs with air gives these creatures better buoyancy and makes floating easier.
Even on land the skin plays a greater part in breathing than the lungs. Frogs are also able to breathe through their skin, with tiny blood vessels known as capillaries that are located under the outer skin layers. The African Hairy Frog has small lungs and during the breeding season, the male frogs of this species are known to get hair on their back legs. This is because it needs a high amount of oxygen during this time.
However, air can be absorbed only through a moist skin. If the skin becomes too dry, the frog will die. Therefore the skin contains glands which secrete a clear mucus or slime whose function is to keep the skin moist and supple.
The skin absorbs water as well as air, for frogs do not drink. Frogs are cold-blooded. That means they are as warm or as cold as the air or water surrounding them. In winter, they hibernate under water, where their body temperature falls, their bodily functions are kept at minimum and breathing is carried on entirely through the skin.