Facts about the animal kingdom

How Do Turtles and Tortoises Breathe?

Nick A. Romero
By Nick A. Romero, Biologist and environmental educator. February 9, 2023
How Do Turtles and Tortoises Breathe?

Within the group of vertebrates we find the order Testudines, to which all turtles belong, both aquatic and terrestrial. They are among the oldest and most primitive of all reptile groups, evolving millions of years ago. They are easily recognized by their hard shell, which protects them from predators. Everyone knows that most mammals breathe through their mouths and noses, and that some reptiles, such as frogs, can breathe through their skin. But what about turtles and water turtles?

In this AnimalWised article, we explain how tortoises and turtles breathe, as well as some other interesting facts about these amazing reptiles.

You may also be interested in: How Do Turtles and Tortoises Sleep?


  1. How do tortoises breathe?
  2. How do turtles breathe?
  3. How long can a turtle survive under water?
  4. Decompression syndrome in sea turtles

How do tortoises breathe?

Tortoises are vertebrates that breathe pulmonarily, that is, they breathe through their lungs. However, their respiratory process is different from that of other vertebrates.

Unlike humans, turtles cannot expand their thorax to allow air to flow in and out. This is because the tortoises' shell is a modified rib cage that forms part of the spine, and its ribs are also fused together. This anatomical feature results in the lungs being connected to the carapace in the upper part, while the lower part is connected to other organs.

Because of the limited movement of the lungs that allows them to move air, tortoises use abdominal and thoracic muscles like a diaphragm to allow air to flow in and out of the lungs. In order for gas exchange to occur, tortoises push and pull air into and out of their lungs.

Studies suggest that the turtle's respiratory mechanism is the result of anatomical evolution, in which structures such as the ribs and trunk muscles divide labor and their function is replaced by other muscles. As for the widening of the ribs, they became the main means of stabilizing the trunk of the animals. It is estimated that this entire process of transformation must have taken place about 50 million years ago, before the carapace developed into a fully ossified structure.

It is worth noting that both sea turtles and land tortoises have a respiratory system consisting of lungs attached to the inside of the shell. This is why it is so dangerous for them to remain upside down on their shells. This way, their lungs would be compressed and would not be able to function properly, much like their heart, which would also not beat normally, causing the animal to suffocate.

You may be interested in this other article, where we explain in detail how to care for a pet tortoise.

How do turtles breathe?

Sea turtles and freshwater turtles are vertebrates that actually belong to the same order as tortoises. Although they are adapted to live in water, aquatic turtles also breathe through their lungs, so they must come to the surface to breathe.

However, both sea turtles and freshwater turtles have evolved other mechanisms for exchanging gasses underwater to take in oxygen. Regardless of how they breathe, vertebrates can barely tolerate a lack of oxygen due to their metabolism. Sea turtles, for instance, wouldn't be able to breathe at depth if they had to surface every few minutes.

Do turtles breathe through their butts?

Technically, turtles do not breathe through their butts. This is because turtles do not have a "butt," but rather a multipurpose opening called a cloaca, which is also used for sexual reproduction and egg laying. They do, however, have a process called cloacal respiration. In less technical terms, this could be interpreted as reproduction through the butt.

Both sea turtles and freshwater turtles breathe bimodally, that is, through the lungs and the cloaca, which is the last part of the animal's digestive system and therefore has branching papillae that allow gas exchange.

In this sense, cloacal respiration is possible because the animal tenses a series of muscles that allow water to be pumped inward through the opening in the cloaca. The water then enters structures known as "cloacal pockets" These are sacs with specialized tissue at the bottom where gas exchange takes place. This means that this is where a turtle takes oxygen from the water and passes it on to the blood.

Do turtles have gills?

Gills are organs used by various aquatic animals to breathe underwater. However, these structures are not part of turtle anatomy because turtles primarily breathe through their lungs.

Do not miss this other article where we explain the different types of sea turtles that exist.

How Do Turtles and Tortoises Breathe? - How do turtles breathe?

How long can a turtle survive under water?

The amount of time a turtle can stay underwater can vary, but thanks to its cloacal respiration, in some cases there are individuals that can stay underwater much longer than any other vertebrate with lung respiration.

Fitzroy River turtle (Rheodytes leucops), for example, can stay underwater anywhere from 10 hours to three weeks. Another example is the painted turtle (Chrysemys picta), which can stay underwater for more than four months.

In general, turtles can spend between four and seven hours underwater resting. Their metabolic needs increase when they are in motion or under stress, so they must surface more frequently to catch their breath.

When aquatic turtles are underwater, they cannot use their lungs unless they rise to the surface. However, there are species of aquatic turtles that can expel oxygen through the membranes in their mouth and throat. This feature is very important for turtles that exercise their torpor (resting state) in water. Since their metabolism is slowed, and they consume little oxygen, oxygen can be supplied through their mouth and throat without having to go outside to breathe.

You may also be interested in this other article, where we discuss how long turtles can live.

Decompression syndrome in sea turtles

Sea turtles do not make stops on the way up to decompress as humans do, but close a sphincter in the pulmonary artery from the beginning of the dive, preventing nitrogen from entering the blood at any time. In this way, sea turtles can dive without dangerous nitrogen bubbles forming in their bodies. However, if the animal is caught in a net, the system can fail. As a result, these turtles suffer from decompression sickness and die within a few days if they are not treated in a hyperbaric chamber.

This finding had major implications for the scientific community and also for conservation, suggesting that many of the turtles caught in the nets and returned to the sea may die soon after. This also means that the real impact of fishing on turtles may be greater than previously thought.

Have you ever wondered what the life cycle of sea turtles is like? Take a look at this other article on the life cycle of sea turtles to learn more about these fascinating animals.

If you want to read similar articles to How Do Turtles and Tortoises Breathe?, we recommend you visit our Facts about the animal kingdom category.

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  • Animal Diversity Web (2020). Available at: https://animaldiversity.org/
  • Jackson DC. (2002). Hibernating without oxygen: physiological adaptations of the painted turtle. J Physiol . Sep 15;543(Pt 3):731-7. Available at: 10.1113/jphysiol.2002.024729
  • Hickman, C.; Roberts, L.; Parson A. (2000). Comprehensive principles of zoology . McGraw Hill Inter-American: Spain.
  • Priest, T and Franklin, C. (2022). Effect of Water Temperature and Oxygen Levels on the Diving Behavior of Two Freshwater Turtles: Rheodytes leukops and Emydura macquarii . Available at: https://doi.org/10.1670/0022-1511(2002)036[0555:EOWTAO]2.0.CO;2
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How Do Turtles and Tortoises Breathe?