Animal Respiration: Skin Breathing

Here you will find information about animals with skin respiration.

What Animals Breathe With Their Skin?

Small invertebrates such as sponges, corals, jellyfish and worms use their skin to breathe.

How Do Animals Breathe With Their Skin?

For skin respiration, the skin has to be moist and thin. Only then it is permeable enough to absorb the oxygen and transport it to all parts of the body through delicate blood vessels. This is called “diffusion” (from the Latin word “diffundere”/”diffuse”). Of course, the used up oxygen (i. e. the carbon dioxide) somehow has to leave the body again – and it takes the same way again: through the skin (see picture below).

Skin breathing Skin breathing - Illustration: Silke/

What are the Advantages of Skin Respiration?

It works under water as well as above the water surface.

What are the Disadvantages of Skin Respiration?

Skin respiration is the most primitive form of breathing. Compared to tracheal respiration and breathing with your lungs, it provides the smallest amount of oxygen. Only small animals use skin respiration. They do not need large amounts of oxygen due to their small body size and metabolism. Those animals have to spend all their time in humid environments so that their skin stays moist.

Goldfish Goldfish - Photo: Mirek Kijewski/Shutterstock

The Skin as a „Backup“ for the Lung

It is primarily invertebrates that breathe with their skin, but there are also vertebrates doing this – but not exclusively. They use two methods of breathing depending on their environment or their current situation. Among those animals are the frogs for instance. In addition to their lungs, they also use their skin to breathe. The bullfrog breathes 80 % with its skin and only 20 % with its lungs. During the winter, frogs primarily use their skin to breathe as they are less active then and thus need less energy. Some more figures:

AnimalSkin Respiration
Amphibians ca. 30 - 60 %
Fish ca. 5 - 30 %
Water snakes ca. 20 - 30 %

The only vertebrate with 100 % skin respiration is the lungless salamander. It does not have any or only rudimentary lungs. By the way: Humans also use their skin to breathe, but only 1 - 2 %. Birds and furred animals even less, only about 0.5 %.