How Do Frogs Breathe? Skin, Lungs and Mouth Explained
Adult frogs breathe in three ways. They fill simple, sac-like lungs by pumping air with the floor of the mouth, a process called buccal pumping. They also exchange gases through thin, moist skin, which is especially important for releasing carbon dioxide. A smaller share of gas exchange happens across the lining of the mouth. Tadpoles breathe with gills and tail fins before their lungs form.
Frogs do not breathe the way you do. They have lungs, but they push air into them using their mouths.
Their skin does a large share of the work too. This guide explains each route, how the balance changes by species and season, and what changes as a tadpole becomes a frog.
How this was made: prepared with AI assistance and checked against the sources listed at the end. Images are AI-generated illustrations, not photographs of real animals or products.
Key Takeaways
- Adult frogs breathe with lungs, skin and the lining of the mouth.
- Buccal pumping uses the mouth floor to push air into the lungs.
- Moist, blood-rich skin lets oxygen and carbon dioxide pass through.
- Carbon dioxide is released mainly through the skin.
- The balance between lungs and skin differs by species and season.
- Tadpoles use gills and tail fins until lungs develop.
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The three ways frogs breathe
Zoology course material from LCWU in Pakistan lists three routes: pulmonary respiration through the lungs, cutaneous respiration through the skin, and buccopharyngeal respiration through the lining of the mouth and throat.
Frogs use all three, but not equally. Lungs matter most in some species. In others, the skin matters just as much. The sections below cover each in turn.
Lungs and buccal pumping
Britannica describes adult frog lungs as simple, sac-like structures. They lack the spongy inner structure found in bird and mammal lungs. The LCWU material adds that frog lungs are subdivided, which increases surface area.
Frogs fill their lungs with a mouth pump, not a rib cage. Britannica explains the steps. The frog lowers the floor of its mouth, which draws air in through the nostrils. The nostrils then close. Raising the mouth floor forces the air through the glottis into the lungs.
Exhaling relies on body wall muscles and the elastic recoil of the lungs. The mouth also pulses between breaths. Britannica says these movements are thought to help the sense of smell by moving air over scent surfaces.
- Lower the mouth floor so air enters through the nostrils.
- Close the nostrils.
- Raise the mouth floor to push air through the glottis into the lungs.
- Exhale using body wall muscles and lung recoil.
Breathing through the skin
Live Science explains that frog skin is thin, moist from mucus glands and porous enough for air molecules to pass through. A network of small blood vessels under the skin takes in oxygen and releases carbon dioxide. Researcher Schwenk, quoted by Live Science, calls this cutaneous respiration.
Britannica adds that carbon dioxide is eliminated mainly through the skin. It also notes that skin on the back and thighs has a richer capillary network than the skin of the underparts.
Gas exchange needs a wet surface, which is why the skin has to stay moist. Live Science says skin breathing helps frogs survive underwater and through long hibernations.
The mouth lining
The third route runs across the moist lining of the mouth and throat. Live Science confirms that frogs also breathe through the lining of the mouth.
The LCWU material gives a wide range for this route, from 1 to 70% of gas exchange across amphibians, but it also says frogs use mouth breathing for only a relatively small share. The wide range shows how much the number depends on the species, so I would not quote a single figure.
How the balance changes by species and season
Britannica gives examples from European frogs. In the common frog (Rana temporaria), lung oxygen uptake is about three times greater than skin uptake. In the edible frog (R. esculenta), lungs and skin contribute about equally.
In the tree frog Hyla arborea, more than 75% of the respiratory capillary surface is in the lungs.
Season matters too. Britannica says that in winter, lower metabolic rates let the skin alone meet gas exchange needs. The LCWU material agrees that skin respiration is especially important in hibernation or estivation, since the lungs are small. Live Science adds that frogs vary in how much they rely on the skin.
| Species | Lung vs skin finding |
|---|---|
| Common frog (Rana temporaria) | Lung oxygen uptake about 3 times skin uptake |
| Edible frog (Rana esculenta) | Lungs and skin contribute about equally |
| Tree frog (Hyla arborea) | Over 75% of respiratory capillary surface in lungs |
Tadpoles and metamorphosis
Britannica says frog tadpoles exchange gases through their gills and through large tail fins that contain blood vessels. Gills and the tail fin degenerate as paired lungs form. Larvae that are changing into frogs make trips to the surface to take air.
Live Science reports a 2020 study by Schwenk and a colleague on very small hatchlings. Those too small to break the water surface make their own air bubbles and push them into their lungs.
Not every amphibian follows this pattern. Britannica notes that the axolotl keeps external gills for life, and lungless plethodontid salamanders breathe entirely through the skin. See our post on tiger salamander vs axolotl for more on salamanders.
Drinking through the skin
Live Science notes that water also enters through frog skin. Many frogs have a highly vascularized “drinking patch” that absorbs large amounts of water. Some desert frogs absorb water in the rainy season, store it and may survive on it for months or years in burrows.
For general frog basics, read the physical characteristics of a frog.
Frequently Asked Questions
How do frogs breathe?
Adult frogs use lungs filled by buccal pumping, thin moist skin and the lining of the mouth.
Do frogs breathe through their skin?
Yes. Blood vessels under thin, moist skin take in oxygen and release carbon dioxide.
Can frogs breathe underwater?
Frogs can take in oxygen through the skin underwater. Adult frogs lose their gills, so skin exchange carries them while submerged.
What is buccal pumping?
It is a mouth-floor pump. Lowering the floor draws air in, and raising it pushes air into the lungs.
Do tadpoles have lungs?
Not at first. Tadpoles use gills and tail fins, and lungs form as the gills degenerate.
Do all frogs breathe the same way?
No. In some species lungs dominate, and in others the skin contributes about as much.
Bottom Line
Frogs breathe with a mix of lungs, skin and mouth lining. The mouth pump pushes air in, and the skin removes much of the carbon dioxide.
The mix shifts with species, activity and season, which helps frogs live in water, on land and through cold winters.
Sources
- Britannica: Respiratory system, Amphibians, accessed Lungs, buccal pumping, skin, tadpoles, species examples
- Live Science: How do frogs breathe and drink through their skin?, accessed Skin structure, cutaneous respiration, drinking patch
- LCWU Zoology course: Amphibian respiratory system, gas exchange and temperature regulation, accessed Three respiratory routes, lungs, hibernation
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