4 Animals That Breathe Through Stomata

The animals that breathe by stomata are those using his pores or openings called spiracles or stigmas as channels for the breathing process.

It is not common to use the term stoma to refer to animal respiration, since this term is better known in reference to the type of respiration typical of higher plants. The terms blowhole or pore are more appropriate when referring to animals that have this type of respiration.

In plants, stomata are pores made up of a pair of specialized cells, the occlusive cells, which are found on the surface of the leaves of most higher plants. These can be opened and closed to control gas exchange between the plant and its environment.

In the case of animals, spiracle respiration occurs mainly in insects and is related to tracheal respiration. 
For its part, respiration through skin pores is observed in animals such as amphibians and annelids, which present a type of skin respiration.

You may also be interested in knowing 12 animals that breathe through gills.

Examples of animals that breathe through stomata (spiracles or pores)


This annelid does not have specialized respiratory organs. The uptake of oxygen and the elimination of carbon dioxide is done through the pores of your skin.


The snail has a very particular breathing hole called a pneumostoma. Through this hole located below the mantle on the animal’s head, the air enters and leaves.

To take inspiration, the pneumostoma is opened and air enters the paleal cavity, filling it with air. To exhale, the pneumostoma is opened again and the stale air is expelled.

The snail also has cutaneous respiration, which is carried out through the surface of the foot that is exposed to the air.

Fruit fly

Its scientific name is Drosophila melanogaster and it is also commonly known as the vinegar fly. His breathing is tracheal and he performs it through the spiracles present in his abdomen.  

Velvet worms

These animals, also known as onychophores, are related to arthropods. Like them, they have a tracheal system to carry out their respiratory process.

But unlike them, their spiracles remain constantly open, since they do not have a mechanism to control them.

Other examples of animals with spiracle or pore respiration are: frogs (cutaneous respiration and lung respiration), newts (cutaneous respiration), grasshoppers (tracheal respiration), ant (tracheal respiration), cicada (tracheal respiration), dragonfly (tracheal respiration) and crab (tracheal respiration).

Also the butterfly (tracheal respiration), caecilian (skin respiration), beetle (tracheal respiration), mites (tracheal respiration), bee (tracheal respiration), silkworm (tracheal respiration), spider (tracheal respiration), millipedes (tracheal respiration) ) and the cockroach (tracheal respiration), among others.

Stomata in animals


The spiracles are small holes that connect the tracheal respiratory system with the outside. They are highly complex structures that can be opened and closed to allow a variable amount of gas exchange. In addition, the accuracy of your control helps prevent water loss.

The spiracles open more frequently and more widely at high temperatures and when activity is increased, in accordance with the increased need for oxygen.

An interesting aspect of these structures is that they do not necessarily all open at the same time, but to the extent that carbon dioxide is produced and oxygen is lost.

Carbon dioxide appears to be the primary stimulus for opening the spiracles. If a small stream of carbon dioxide is directed towards a particular blowhole, only this blowhole will open. This shows that each blowhole can respond independently.

The spiracles are always found on the sides of the insects and are located in the thorax and abdomen.

They are aligned in pairs and there can be from 2 to 10 pairs. There is always at least one pair that is located in the thoracic area and the others are present in the abdominal area.

The structure of spiracles can consist in its simplest form of a hole that connects directly with the trachea. In its most complex form, the externally visible hole leads to a cavity known as the atrium that connects to the trachea.

The walls of the atrium are often covered by filtering hairs or lamellae. In some animals, the blowhole is covered by a sieve plate that contains a large number of small pores. Both the hairs and the sieve plate serve to prevent the entry of dust, microorganisms or water into the trachea of ​​the animal.


The pores, like the spiracles, are small holes that are scattered by the external tissue or skin that covers the body of an animal. These holes are the outer openings of the sweat glands.

However, in cutaneous respiration animals they are the channels that allow gas exchange between the exterior and internal respiratory cells or tissues.

Skin-breathing animals (such as the earthworm) do not have specialized organs for breathing. So they breathe through their skin. This is thin, moist, highly vascularized and permeable to gases.

The skin must remain moist all the time so the glandular cells secrete a mucus that flows to the outside through the pores.

Likewise, coelomic fluid flows abundantly through the dorsal pores, which also contributes to the maintenance of body moisture.

This moisture allows the pores to remain open and the animal can absorb oxygen and eliminate carbon dioxide.


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  2. Schmidt, K. (1997) Animal Physiology: Adaptation and Environment. Cambridge, UK: Cambridge University Press. Recovered from books.google.co.ve.
  3. Chapman, R. (2013). The Insects: Structure and Function. Arizona, USA: Cambridge University Press. Recovered from books.google.co.ve.
  4. Sloane, E. (2002). Biology of Women. Albany, USA: Delmar Thomson Learning. Recovered from books.google.co.ve.
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