Deep Breath: Can Sea Turtles Breathe Underwater?

can sea turtles breathe underwater

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Sea turtles have lungs, but the constriction of their shells does not allow their diaphragm to expand. Instead, muscles lining the inside of their shells help to push the air in and out.

This is extremely interesting, and as sea turtles are an endangered species in many places, it is important to learn as much as we can about their way of life.

So when you ask can sea turtles breathe underwater?

No, but the metabolism slows down and they can remain submerged for a long time. Due to the fact that they are cold-blooded, they manage to stay submerged.

They breathe through their cloaca near the tail an area usually associated with excretion.

The cloaca is rich in blood vessels, however, the sea turtle must swim to the surface every few minutes to breathe when active.

Can Sea Turtles Really Breathe Underwater?

it is impossible for a sea turtle to breathe underwater, holding their breath causes the heart rate to slow right down and the heart may only beat every 9-10 minutes, and some species of sea turtles rest for 11 hours a day.

In the trachea of the turtle, two bronchi connect the heart and the lungs to deliver the air.

The muscles inside the shell push the air out and in again, and the ribs are unable to move due to the construction of the turtle’s shell.

If the turtle stays submerged for too long or becomes trapped, it can drown as they don’t have gills like fish, instead, they have lungs.

Sea turtles have lungs similar to those of other reptiles, and they work effectively to exchange oxygen and carbon dioxide.

In fact, the turtle will often go to sleep in the water for about one hour without breathing. They are not using much energy so require very little oxygen enabling them to rest and then come to the surface for air.

The sea turtle may be in the ocean for some time as they tend to return to, and nest in the same place every year, this is known as natal homing behavior and the exact mechanism is unknown.

So we have established that no sea turtles breathe underwater, because they don’t have gills, and need to return to the surface for air.

How Do Sea Turtles Breathe?

The lungs of a sea turtle are similar to those of a reptile and different from that of humans and mammals, the lungs are located under the carapace and the vertebral column.

The sea turtle breathes by relaxing and contracting specific muscles like the intercostals that are attached to the rib cage and expand and contract the body wall.

The shell cannot expand due to its rigidity. and certain adaptions for respiration have evolved.

Many turtles spend large periods of time underwater they must resurface to fill their lungs, and expel air.

Turtles have a linked circulatory and pulmonary system, and a three-chambered heart pumps blood through the lungs and returns oxygenated blood to the body.

Can sea turtles breathe underwater would seem like quite a sensible question when they spend so much time there, however, they do come up to breathe depending on the use of energy which seems to dictate the amount of oxygen required by the sea turtle, and in times of low activity this is less frequent.

Sea turtle respiration remains aerobic during the dive time in the ocean, and their large lungs enable them to fill the lungs with air when surfacing and rapidly exchange oxygen avoiding trapping gases when deep diving.

When sea turtles hibernate during the cold winter months, they use cloacal respiration by diffusing oxygen and carbon dioxide out through their cloaca.

When winter comes turtles will often hibernate for 6-8 months depending on latitude, and during that time they conserve a lot of energy.

Can Sea Turtles Drown?

If the sea turtle becomes trapped underwater it can drown, as it does need to take a breath eventually, and when it has become entangled in plastic or fishing gear the activity of trying to get out depletes its oxygen supply causing rapid drowning to occur.

The sea turtle maintains an internal environment hypotonic to the ocean and to do this they must excrete excess salt.

This is done through a lachrymal gland found in the eye cavity enabling tears with a high salt concentration to be produced and shed.

The salt content is higher than the salt levels found in seawater, and this is a form of Osmoregulation used to induce a hypotonic state.

When the ocean becomes very cold in the Pacific, Green Sea Turtles haul themselves out of the ocean on remote islands to bask in the sun.

They do this to maintain a higher body temperature than the water, and this behavior has been observed in Hawaii and parts of Australia and is thought to aid thermoregulation.

Habitat Of Sea Turtles

The sea turtle is usually found in the waters over the continental shelves, and the first few years of their lives are spent floating in seagrass in the pelagic zone.

They find food in the Sargasso grass or Sargassum Seaweed mats. When they reach adulthood they come in nearer to the shore

Some sea turtles live for 100 years or longer and eat a wide variety of plant and animal life including jellyfish and sponges.

The leatherback sea turtle controls the jellyfish population, preventing it from getting out of hand.

When the turtles breed the female digs a hole in the sand with her flippers and lay 50-300 eggs and then the nest is refilled with sand. She then returns to the ocean leaving the nest unattended.

Final Thoughts

Sea turtle breathes through their lungs, so during times of activity like swimming and feeding, they will need to surface regularly.

Their lungs are large allowing rapid oxygen exchange to take place when they reach the surface, and being able to slow their metabolism, conserves oxygen and contributes to their long life span.

Hopefully, you’ve enjoyed this post and now have a clear answer to can sea turtles breathe underwater.