20 ANIMALS THAT BREATHE THROUGH LUNGS (PULMONARY RESPIRATION) - BIOLOGY - 2025

Some of the most common lung-breathing animals are the duck, chicken, dog, elephant, frogs, crocodiles, and turtles. Respiration is the process by which living beings take in oxygen (O ₂) and exhale carbon dioxide (CO ₂), to keep their body active. It enters through the respiratory tract, reaches the lungs and oxygenates the blood. It is exhaled through the mouth in the form of CO _2.

Mammals are one of the species capable of breathing through the lungs. They are mostly terrestrial and there are also aquatic ones. Birds and reptiles also have lung respiration, as do some amphibians like frogs and mollusks like the snail.

Mammals can live in water and on land. Cetaceans are the animals that live in the sea and to be able to breathe, because they cannot do it under water, they must rise to the surface, take the required oxygen and submerge again.

Terrestrial and flying mammals, such as bats, carry out the process of inhaling O ₂ and exhaling CO ₂. Amphibians have 3 types of respiration: cutaneous, oropharyngeal and pulmonary. The latter is the simple use of the pair of lungs. The left lung is usually longer than the right.

Reptiles have long lungs and are internally divided into several chambers. The lining of the lungs may be covered with numerous small sacs called alveoli.

These increase the inner surface of the lungs, increasing the amount of oxygen that can be absorbed. In many snakes, only the right lung is actively working. The left lung is reduced to non-functional sacs or they are completely absent.

In contrast to mammals, the lungs are rigidly incorporated into the thorax. Although the pleura is present in an embryonic stage, it later regresses. The lung is not arranged in lobes and during respiration, its volume does not change.

The respiration of the birds takes place in attached air sacs that carry it towards the lungs. Gas exchanges do not occur in air sacs. These bags are very thin with transparent walls. Apart from their breathing motor function, they are involved in the formation of sounds.

Different species of animals that carry out lung respiration

- Birds

Robin

Bird of European origin, it has nostrils through which O ₂ enters and passes to the pharynx, then to the bronchi, it passes to the lungs.

Air sacs allow air to enter and exit, without any exchange within them. They allow them to have air to meet their energy requirements.

Quail

The nostrils are present at the base of the beak, protected by fine feathers that serve as a filter and prevent the entry of foreign particles.

O ₂ passes from the fossae to the trachea, through the larynx. In the trachea, there is a division for O _{2 to} enter the lungs, which are underdeveloped.

Hen

They take the air through the nostrils, passes through the larynx and then into the trachea, it divides into two main bronchi to reach the lungs.

O ₂ enters the anterior air sacs and passes to the posterior air sacs, emptying into the lungs.

Duck

It breathes in a similar way to other birds, the O ₂ passes through the nostrils, 75% of it remains in the anterior sacs and 25% goes from the posterior sacs to the lungs.

Ostrich

Their way of breathing is similar to that of other flightless birds, passing through the nostrils, the larynx, the trachea until reaching the lungs, where they carry out gas exchange, inhaling O ₂ and expelling CO ₂.

- Mammals

Dog

The absorption, transport and exchange of gases is carried out. O ₂ passes through the nasal cavities, larynx, pharynx, trachea and bronchi until it reaches the lungs where gas exchange takes place. CO ₂ is exhaled through the intercostal and abdominal muscles.

Elephant

Through its tube, it takes the O ₂ which is transported to the trachea and from there it goes to the lungs, where the gas process takes place, until the CO ₂ is extracted.

Horse

O ₂ enters through the nasal passages, passes through the pharynx, trachea, bronchi and later to the lungs. Gas exchange occurs in the bronchioles (within the bronchi).

Dolphin

It is one of the mammals that lives in water and requires going out to take O ₂ through a hole in the top of its head called a blowhole.

From there it passes to the larynx, then the trachea, the bronchi to the lungs. Breathing is voluntary.

Whale

It is a mammal that lives in water, it has lungs, it must go to the surface to take O ₂ through a hole in its head, submerge and come back out to take it to stay energized, similar to that of the dolphin. They exchange 80% to 90% of the air contained in their lungs.

- Amphibians

Frog

Its respiration is initially through gills, then it passes to pulmonary and cutaneous. Take advantage of the night to recover water losses during the day. O ₂ enters through the nostrils.

Toads

O ₂ enters from the nostrils, the surface of the mouth rises to carry air into the lungs.

Subsequently, the gas exchange takes place in the lower part of the mouth, the air is removed from the lungs, passes into the mouth and passes again through the nostrils.

Salamanders

As adults, they breathe through their skin and lungs. It breathes in a similar way to other amphibians.

Axolotls

They have gills and lungs. The latter uses them when it goes to the surface, takes O ₂ and keeps floating, like other amphibians.

Cecilias

They live in swamps, in their adult life they breathe through their lungs, they take in O ₂ from the air of the environment that surrounds them.

- Reptiles

Snakes

It takes the air that reaches the trachea, the right lung, being the most extended, is the one that performs the breathing process while the left is little used.

Crocodiles

They have a muscle that carries air to the lungs on inhalation. The liver then helps the process by sending CO _{2 forward}.

Alligators

The air flow goes in only one direction when inhaled into the lungs. This is due to the evolution of this organ that has allowed it to stay alive.

Sea turtle

You ascend to take in air from the surface, which allows you to dive for more than 5 hours to depths where you can lower your heart rate and with the air in your lungs, breathe and ascend.

Morrocoy

It is terrestrial. They breathe through the mouth, passing the air through the trachea, reaching the bronchi and in turn the lungs.

References

1. Alamidi, D. (2010). Lung imaging using oxygen enhanced MRI in small animals. Gothenburg, University of Gothenburg.
2. Breathing of Men and Animals. Recovered from: e-collection.library.ethz.ch.
3. Animal classification. Recovered from: esisthenio12.jimdo.com.
4. National Institute of Educational Technologies and Teacher Training: The Breathing of Living Beings. Recovered from: sauce.pntic.mec.es.
5. Noguera, A. and Salinas, M. Biology II. Mexico City, Colegio de Bachilleres.