Frogs are amphibians, so along with toads, salamanders, and newts, they can live both in the water and on land. But what about breathing? Are frogs capable of exchanging gases required for life when submerged? Here is all that you will want to know.
So, do frogs breathe underwater? Frogs do breathe underwater and do so by absorbing oxygen through their skin. Most frog species also have a separate system that allows them to breathe through their lungs when out of the water. However, as frogs have lungs, they are still susceptible to drowning if their environmental conditions are not right.
Even frog species that are predominantly land-dwelling have the incredible ability to survive underwater for hours at a time.
It’s nothing short of amazing.
Frogs possess unique biological features that allow them to breathe underwater comfortably. This process is called cutaneous respiration.
Nevertheless, the length of time a frog can remain underwater ranges. It is dependent on several factors, including the species of frog and even the water temperature too.
Let us now take a closer look at breathing in frogs predominately in and around the water!
Be sure to keep reading; this is absolutely fascinating!
- 1 How Does A Frog Breathe Underwater?
- 2 How Long Can Frogs Stay Underwater?
- 3 Can Frogs Live Completely Underwater?
- 4 Do Frogs Need To Breathe Air?
- 5 Can Frogs Drown?
- 6 Finally
How Does A Frog Breathe Underwater?
All frogs begin their lives as fully aquatic tadpoles that use temporary gills for respiration. These gills are situated on the sides of a tadpole’s head and are usually covered with a thin flap of skin.
As a tadpole grows, its fragile skin stretches to form a larger permeable layer of skin over its new form, which frogs can then breathe through.
During this metamorphosis, a tadpole’s gills are also transformed into internal organs.
Lungs are also developed which allows the frog to breathe outside of the water.
Just under a frog’s skin is a huge network of blood vessels and capillaries which take the absorbed oxygen and distribute it through the body.
Once the blood cells have released the oxygen, they absorb carbon dioxide, which is then expelled out through the skin.
This process accounts for over half of the respiration in adult frogs and can be performed both in and out of the water.
The only requirement is that a frog’s skin must be moist for it to occur.
The whole process from tadpole to fully developed frog can take anywhere from two months to three years, depending on the species.
Very few tadpoles can survive out of water; however, there are exceptions!
The Sri Lankan Rock frog is one of the very few frog species whose tadpoles live on land.
These frogs lay their eggs near a water source so their tadpoles can hunt along the riverbanks.
This species is now considered to be extremely vulnerable in the wild.
You will rarely ever see a frog basking in the sunshine as the sun’s rays can absorb all the moisture from their skin.
If a frog’s skin dries out completely, they can no longer breathe through the cutaneous respiration process, which can be fatal.
This is why you will often see frogs soaking in shallow pools of water or frequenting damp marshes or swamps and why many species are nocturnal.
How Long Can Frogs Stay Underwater?
The truth is, no one really knows how long frogs can remain underwater because no studies have yet been carried out to find out the answer. What we do know is the length of time varies between species and their level of activity.
Given that frogs have a unique system that allows them to breathe underwater, you would have thought that they would be able to remain submerged indefinitely.
However, there are several factors that can affect how long a frog can breathe underwater.
The number one factor is the oxygen level in the water.
Oxygen Levels In The Water
If this is low, frogs cannot remain underwater for long because there is simply not enough oxygen to absorb.
When this happens, frogs will need to surface immediately to breaths through their lungs.
Oxygen is produced in water through movement, so many frogs will only soak for a short time because water bodies are typically quite stagnant.
The second factor is temperature.
In warmer waters, a frog’s metabolism will increase, increasing the oxygen demand.
Frogs can generally stay underwater for longer if the surrounding temperature is cold because the temperature drop will decrease their metabolism rate.
Thirdly, most aquatic species appear to have a thinner skin membrane than their terrestrial counterparts, making sense as thinner skin would allow for more effective oxygen absorption.
These frogs are particularly susceptible to drying out, so handling must be kept to a minimum.
Always ensure your hands are clean, and it is a good idea to dip them into your frogs’ water before handling them.
Season and Hibernaiton
A frog’s unique respiratory system especially comes in handy in winter months when food is scarce, and hibernation becomes necessary.
Hibernation is a process whereby certain animals slow down their metabolism so they can ‘sleep’ through the winter while ensuring they are safe from predators.
Aquatic frogs generally hibernate at the bottom of lakes and ponds amidst oxygen-rich water.
They don’t often bury down beneath pond substrate or mud as this would lower available oxygen levels dramatically.
They may even swim around from time to time during hibernation to ensure there is enough oxygen to sustain them through the winter.
Frog species such as the Leopard frog (Rana pipiens) and the American bullfrog (Rana catesbeiana) hibernate this way.
Terrestrial species either bury down below the frost level of soil or find rock crevices or deep leaf piles to wait out the winter.
Incredibly, even if these frogs do get exposed to minus temperatures, they do not fully freeze over.
This is because they have their very own built-in anti-freeze!
The North American Wood Frog can survive in a near-dead state for up to seven months in sub-zero temperatures by using a concoction of stored urine and glucose, which prevents their cells and vital organs from freezing.
During this time, their brain, heart, and lungs effectively shut down.
Then when spring appears, they simply defrost and head off to find a mate!
Can Frogs Live Completely Underwater?
Most frogs can stay underwater for long periods; however, only a few species can be considered truly aquatic and live predominately underwater.
The African Dwarf Frog, for instance, lives its entire life underwater but still needs to rise to the surface to breathe in air, as they have lungs, not gills.
These incredible creatures can remain underwater for up to seven hours at a time before they need to surface to take a breath, which is pretty impressive!
They have also evolved to have webbed feet, which they use to shovel food into their mouths, and strong legs ideal for swimming.
If you like the idea of owning one of these frogs, you must be able to provide an enclosure with a large body of water, approximately 10 gallons per frog which is roughly 44 liters.
These frogs cannot survive outside of the water for long; in a low humid environment, they can only last up to 20 minutes on land before they dry out too much, and the situation becomes fatal.
They are also very sensitive to water quality, so a good strong water pump is essential for this species. Water temperature must also be kept between 70-78° Fahrenheit (22 and 26 degrees Celsius.)
These frogs belong to the family Pipidae, consisting of 41 species of primitive frog lacking tongues and teeth.
They use their sharp claws instead to rip up food items to be ingested.
These species are fully aquatic and have lateral lines running down their bodies, which help them sense subtle vibrations and movements in the water.
The largest aquatic frog globally, the rare Lake Titicaca’s Frog, has taken evolution one step further.
Their bizarre appearance comes from extra layers of loose skin that create folds and flaps across their entire surface.
This adaptation allows these frogs to survive in the poorly oxygenated waters of Lake Titicaca, situated 3000 ft up in the Andes mountains on Bolivia and Peru’s border.
The skin folds create a larger surface area for cutaneous respiration to take place, allowing them to absorb as much oxygen from the water as possible.
These frogs prefer to spend most of their time on the substrate at the bottom of the lake (at least 10 meters below the surface). However, they have been found up to 100 meters down!
These frogs have perfected the skill of skin breathing so well that they do not use lungs at all.
They have even been known to perform underwater push-ups to ensure the water reaches into every one of their many skin folds.
Unfortunately, they are now classed as critically endangered due to water pollution, habitat loss, and over-harvesting for human consumption.
Do Frogs Need To Breathe Air?
Practically every frog species needs to breathe air. Even aquatic species need to come up to the air surface when oxygen in the water is low.
There are, in fact, three different ways that respiration occurs in a frog:
Through The Mouth
This process is scientifically known as Bucco-pharyngeal respiration and occurs through the buccal cavity (the inside of the mouth), which has a mucoid membrane and a network of blood capillaries.
This type of respiration does not involve the lungs but works via a diffusion process similar to cutaneous respiration that occurs through the skin.
Oxygen is absorbed and dissolved in the mucus and is then released into the blood capillaries.
This type of respiration is normally occurring when the frog is submerged in water, but its mouth sits above the surface.
Through The Lungs
Terrestrial frog species will breathe through their lungs when out of the water, although, unlike humans, frogs can choose when lung breathing is necessary.
This breathing type is particularly beneficial for more active frogs that require more oxygen than cutaneous respiration can provide.
A frog’s lungs are relatively undeveloped compared to human lungs, and they do not have a diaphragm to help facilitate breathing.
Instead, frogs use their throats, mouths, and nostrils together to help inhale oxygen and expel carbon dioxide.
To take in air, frogs will expand and relax their throats, which causes air to rush in through the nostrils.
Frogs then simply gulp the air by contracting the bottom of their mouths!
Through The Skin
Also called cutaneous respiration, which occurs via a process known as osmosis.
Tiny holes in the frog’s skin allow oxygen to be absorbed straight into their bloodstream, which is then carried around the frog’s body.
Carbon dioxide is then expelled through the same process.
Frogs generally only use their lungs when in active mode. For example, when they are jumping or climbing.
When at rest or in the water, their preferred method of breathing is cutaneous respiration through the skin.
Can Frogs Drown?
Unfortunately, frogs can drown. This typically happens when the oxygen in the water is too low. Terrestrial frogs like Pacman frogs and tree frogs are more susceptible to drowning than their more aquatic counterparts.
Thus, if you take care of terrestrial frogs as pets, it’s vital only to provide them with a shallow bowl of water to soak in.
The water only needs to be an inch or two deep and wide enough for the frog to fully rest in.
This is because the main area responsible for water absorption, known as a seat pouch, is situated on their bellies, so this area must be able to sit under the water’s surface.
Always make sure there are several easy exits from the water; gentle sloping ramps or low rocks surrounding the water’s edge are both suitable for most species.
Water must also be changed regularly and be free from chemicals to avoid any type of toxin absorption. Whether through the skin or drinking.
Bottled water is considered to be the safest for frogs as it does not contain chlorine, but tap water can be used after it has been left for 24-48 hours for the chlorine to evaporate.
Maintaining a constant temperature in the water is another important consideration as the temperature can change the speed of a frog’s metabolism and, therefore, their oxygen needs.
Underwater thermometers are readily available from most pet stores and are recommended for aquatic or semi-aquatic frogs.
Frogs do breathe underwater, but for how long and when depends entirely on the species, environment, and water conditions.
As such, some frogs are much more capable of under the water than others.
And some frog species have evolved to be more ‘aquatic’ in nature.
As you can see, breathing in frogs is very complex.
If you currently or intend to keep frogs as pets, it’s therefore essential to familiarize yourself with your species.
You will need to optimize the environment accordingly.