Frogs have thin skin because they need it to be permeable to oxygen and carbon dioxide. The skin of a frog is a major part of their respiratory system, which is also why the skin must be kept moist at all times. Frogs can breathe in both water and air with their skin, while their lungs and the inner surfaces of their mouths are also used when on land.Continue Reading
A healthy frog's skin is never dry, and they secrete mucus in order to keep it moist. Many frogs are restricted to environments with plenty of water around, although some have adapted to much drier climates. When dissolved gases are absorbed by a frog's wet skin, they are readily taken up by the network of blood vessels underneath.
The gas exchange of a frog's skin is aided by their mouths and lungs in air, although the lungs are used only occasionally when resting. The lungs are primitive and relatively inefficient. Frogs lack a diaphragm or any rib muscles to expand their body cavity and draw air in. Instead, in cases where the lungs are used, air is drawn into the mouth by lowering the floor of it. The nostrils are then closed and the air is pushed into the lungs. Reversing the process draws the air back out.Learn more about Frogs