Amphibians are known to be to spend parts of their life on land and in water.
In fact, most amphibians start life as larvae living in water before they finally live on land. And frogs are amphibians, so can frogs breathe underwater? Well, yes they can.
The answer is however not straightforward. Juvenile frogs including tadpoles and froglets have gills that allow them to breathe underwater as a fish would.
However, frogs lose these gills and develop lungs. As you may already know, lungs cannot respire water.
However, mature frogs are still able to breathe underwater through their skin at a limited capacity.
Table of Contents
Tadpoles have gills and can respire underwater
Juvenile frogs are known as tadpoles and froglets. Tadpoles are larvae frogs.
All amphibians have a larvae stage. Over their life, they develop from eggs to larvae to frogs.
By the time, the larvae have developed four legs, their lungs would have almost disappeared.
This process can be seen in the image above. Frogs start as tadpoles with gills. With time the gills disappear and the tadpole grows limbs.
Finally, the tail disappears and the tadpole becomes a frog. This process is known as frog metamorphosis because the frog metamorphoses.
First, frog eggs are laid in a large group known as frogspawn or toadspawn, depending on the species.
It’s called frogspawn because it spawns frogs and toads (toads are types of frogs). Inside the eggs, the frog/tadpole develops.
Once the tadpole has developed enough they emerge from the eggs. At this stage, the tadpole has gills, a mouth, and a tail.
They use their gills to respire underwater. They used their mouth to eat, and they use their tails to move in their aquatic habitat. At this stage, the tadpoles are herbivorous and feed on plant matter.
Although they begin with no legs, they start to grow legs. They first develop back legs and then finally front legs.
After that their tails begin to vanish and skin develops over their gills while they develop lungs for breathing air.
In no time, they lose their gills and have fully developed lungs and eardrums. Once at this stage, they venture onto land and stop respiring water through their gills.
Of course, not all frogs leave their aquatic habitats. Interestingly, some frogs are aquatic and remain in their waterbodies over the rest of their lives.
These still breathe air. They resurface every now and then to breathe air.
Terrestrial frogs and tree frogs however leave their aquatic habitats behind as they start their lives as arboreal species or land species.
Breathing Underwater Supplements Breathing Air (In Adult Frogs)
Tadpoles are frogs and they breathe underwater exclusively. Adult frogs can also breathe underwater through their skin but at a limited capacity.
Even aquatic and semiaquatic frogs still need to resurface to breathe air or else they will die from lack of oxygen. For adult frogs breathing underwater simply supplements their oxygen supply allowing them to stay underwater for longer before resurfacing.
Respiration through the skin
For the sake of using the correct terminology, frogs respire underwater as breathing refers exclusively to respiring air using the lungs. Since frogs do not use lungs to respire when underwater, they are technically not breathing.
So how then do frogs respire underwater? As we have already established, frogs can respire underwater.
They do this by exchanging gas through the skin and directly into their blood. This form of respiration is known as cutaneous respiration.
Cutaneous respiration is also known as skin breathing. The term skin breathing explains all we need to know about this respiration type.
Some frogs use cutaneous respiration extensively. Examples are water frogs such as Telmatobius culeus (Titicaca water frog) and Hymenochirus boettgeri (African dwarf frog).
Telmatobius culeus have extensive skin folds that ensure a higher rate of gas exchange. You can notice this from the image below.
While few frogs rely solely on skin breathing to survive, there are some such as Telmatobius culeus that rely heavily on it since it has tiny lungs. Barbourula kalimantanensis (Bornean flat-headed frog) truly has no lungs and relies on cutaneous respiration to respire.
Barbourula kalimantanensis (Bornean flat-headed frog) is the first frog discovered to truly have no lungs. This discovery was made by Djoko Iskandar and David Bickford.
Other adult amphibians have no lungs and rely solely on skin breathing. Examples of this include species from the family Plethodontidae.
These are known as lungless salamanders. This family includes hundreds of species within the family Plethodontidae.
Frequently Asked Questions
Can frogs drown?
If frogs can breathe underwater, can they drown? This depends on the development stage of the frogs and the species.
Tadpoles cannot drown in water as they have gills they use to breathe. Similarly, lungless frogs such as Barbourula kalimantanensis (Bornean flat-headed frog) cannot drown.
Similarly, Telmatobius culeus (Titicaca water frog) won’t drown under most conditions. However, almost all adult frogs can drown when underwater for too long.
Frogs need to breathe air. This includes all pet aquatic frogs so take note.
How long can frogs hold their breath?
As established, frogs can respire underwater but only at a limited capacity. What this means is that frogs need to resurface every now and then to breathe air.
While underwater, frogs hold their breaths and respire through their skin. This is not sustainable.
However, how long can adult frogs stay underwater before needing to resurface to breathe? Well, adult frogs can stay underwater for anywhere from four to seven hours. After which, they need to resurface.
Tadpoles on the other hand can stay underwater indefinitely until they are no longer tadpoles. Also, there are two frog species, Barbourula kalimantanensis & Telmatobius culeus, that can stay underwater indefinitely.
Both frogs aren’t kept as pets and are quite rare so any frog you are likely to come across needs to surface to breathe.
Barbourula kalimantanensis is the only known lungless frog and is endemic to Kalimantan (specifically the Kapuas River basin) which is found on the island of Borneo. It is an endangered species.
Telmatobius culeus is endemic to Lake Titicaca in the Andes. Under the right conditions, this species can stay underwater indefinitely.
The right conditions involve high oxygen content in the water it inhabits. When oxygen levels are low, it will need to resurface to breathe.
What are some great aquatic frogs to keep as pets?
Aquatic frogs live underwater. These can be completely aquatic or semi-aquatic.
Aquatic frogs require aquariums. The best aquatic frogs to keep as pets are the African dwarf frog (Hymenochirus boettgeri), the African clawed frog, the western clawed frog, and the western dwarf clawed frog.
The African dwarf frog is actually the Zaire dwarf-clawed frog or the Congo dwarf-clawed frog. This frog is endemic to the Democratic Republic of the Congo, Central African Republic, Equatorial Guinea, Nigeria, Gabon, and Cameroon.
The African clawed frog (Xenopus laevis) is endemic to Subsaharan Africa from Sudan to South Africa. The western dwarf-clawed frog (Hymenochirus curtipes) is endemic to the Republic of the Congo and the Democratic Republic of the Congo. The western clawed frog (Xenopus tropicalis), also called the tropical clawed frog, is endemic to West Africa and a small part of Central Africa.
How do tadpoles breathe underwater?
Technically, tadpoles respire underwater.
They do this using their gills. So tadpoles breathe underwater using their bills.
How do adult frogs breathe underwater?
Technically, adult frogs respire underwater. Adult frogs respire underwater through their skin using a respiration method known as cutaneous respiration, which is also known as skin breathing.
The term skin breathing explains almost all we need to know about this respiration type. The adult frogs respire through their skin.
Do frogs have lungs?
Frogs have lungs and this is how they breathe on land.
While they are tadpoles, they do not have lungs. The lungs develop over time as they metamorphose from tadpoles to adult frogs.
Terrestrial frogs rely solely on their lungs to breathe. Even aquatic and semiaquatic frogs rely on their lungs to breathe.
There is only one frog that doesn’t have lungs and this is Barbourula kalimantanensis. All other frogs have lungs and there are over 4000 species of frogs in the world.
The lungs of frogs are well developed and play a major role in the lives of the animal.
Conclusion
While frogs can breathe underwater, there are several catches to this. mature frogs can only respire water at a limited capacity. The exchange of oxygen and other gases is done through the skin.
This means that mature frogs cannot respire underwater as efficiently or effectively as fish or tadpoles and froglets do. Also, juvenile frogs such as tadpoles and froglets have gills.
These gills are similar to the ones that fishes have. This allows such juvenile frogs to respire effortlessly underwater.
However, by the time the frog has matured, the gills would have disappeared. While frogs can breathe underwater, it is at a limited capacity and frogs need to resurface and breathe air in order to survive.