How amphibians breathe

Amphibians are the result of the evolutionary transition that, for millions of years, allowed the passage of those animals with aquatic habits to colonize each and every one of the terrestrial environments of the planet. Therefore, the characteristics of current amphibians reflect their properties of aquatic-terrestrial animals . These are some of the main characteristics of amphibians :

• They are cold-blooded animals, capable of adapting their own body temperature to that of the environment.
• Their eyes have lids and tear glands, as well as pupils in both portrait and landscape orientation.
  
• The tongue of amphibians is forked, and they have mandibular teeth in their mouths.
• They have eardrums and structures like vocal sacs for croaking.
• Amphibian skin is usually soft and moist, they lack scales and have various glands that allow them to both defend themselves and avoid drying out by lubricating substances. In addition, amphibians have pigments in their skin that they use to mimic themselves by changing color, as well as to regulate their body temperature, protect themselves from the sun’s rays and be able to sexually recognize individuals of the same species.
• Some amphibians have interdigital membranes on their legs, which help them to move with greater agility.
• Regarding the reproduction of amphibians, it should be noted that the vast majority of amphibian species reproduce by external fertilization of the eggs (anuran amphibians), although some carry out internal fertilization (urodelis amphibians).
• One of the most striking characteristics of this group of vertebrates is, without a doubt, the metamorphosis of amphibians . This incredible process entails the change of anatomy and behavior of amphibians, throughout their development. From the soft gel-covered eggs that have been fertilized by adult amphibians, tiny tadpoles are born capable of swimming and breathing oxygen from the water through their gills. During their growth, they develop legs and tails, and begin to rise to the surface to also breathe oxygen from the air, thus gradually losing their gills and developing lungs. Juvenile amphibians continue to mature and adapt to terrestrial life, until they become sexually mature adults ready to begin the life cycle anew.

In these other articles we explain the Difference between reptiles and amphibians and which animals are amphibians and where they are found .

Amphibians, due to their aquatic and terrestrial habits, have been able to develop different types of respiration throughout their evolution.

In the vast majority of adult amphibians, respiration takes place by exchanging gases through the lungs and skin. However, there is a group of salamanders that do not have lungs and therefore, their respiration is cutaneous , through the skin.

As for the individuals that are in the larval stage, they present gill respiration adapted to the aquatic environment in which they inhabit. The gills are sometimes maintained during the adult stages of certain amphibian species, although the most common is that amphibians go from having a gill respiration to a pulmonary respiration , through the interesting and surprising process of metamorphosis of amphibians.

Like any aerobic animal, amphibians carry out the respiration process to have the oxygen necessary for their survival. This vital process based on the exchange of gases oxygen (enters the body) and carbon dioxide (leaves the body), has different types of respiration processes in amphibians :

• Cutaneous respiration: found in humid environments, many amphibians make use of their permeable and vascularized skin to breathe, carrying out the gas exchange that allows them to acquire the necessary oxygen to survive. In this other post we show you 16 animals that breathe through the skin .
• Buccopharyngeal: thanks to the presence of oropharyngeal membranes (located in the mouth and pharynx of the amphibian), permeable to oxygen and carbon dioxide, both salamanders and some anurans cover their respiratory needs.
• Lung respiration: both frogs and toads have well-developed lungs in adulthood. These are elastic, with air chambers (alveoli) and the ability to pump oxygen that enters through the mouth and nostrils of the amphibian, until it is rapidly expelled in the form of carbon dioxide.
• Branchial respiration: the gills, external respiratory organs, are used by those amphibians that are in the juvenile or tadpole phase, as well as by those adult individuals that spend most of their lives in aquatic environments. These gills have a structure of evaginations in direct contact with the water, so that the gas exchange takes place constantly, through the gill filaments. Meet +40 animals that breathe through gills in this other post .