Home / AMERICAN NEWS / Why Do Some Turtles Breathe Through Their Anuses? – ‘The Why’

Why Do Some Turtles Breathe Through Their Anuses? – ‘The Why’

Welcome to the newest edition of  The Why.  Why do some turtles breathe through their anuses?” you ask? It might seem like the questioner here is talking out of his . . . well, you know . . . but in the case of such creatures as North American eastern painted turtle and the Australian Fitzroy river turtle it’s an honest enough inquiry. Both of these turtles do indeed breathe through their back ends when they so choose.

Why can some turtles breathe through their anuses?  (Where did you get this question!?  Animal Planet?!)  They do so because they can. Why they choose to sometimes breathe out their butts when their mouths work perfectly fine is another question.

why do some turtles breathe through their anuses

North American eastern painted turtle/Image: Sofo

(Oddly, this was actually easy to research.)  According to online sources when researchers put a little bit of food coloring in the water close to the turtles they learned that the turtles were actually taking in water from both ends and sometimes just from the back end. Before we continue, however, accuracy insists that we note that the back end is not really an anus. It is actually something called a cloaca.

A cloaca is not really an anus. It’s a multi-purpose opening. The turtle does everything through this hole: excretes, lays eggs and urinates. So with all that already going on there it simply begs the question: Why do some turtles breathe through their anuses?

Again, with all that other stuff going on back there why doesn’t it just use its mouth to breathe? Why do some turtles breathe through their anuses? Research indicates that the answer could very well be connected to the turtle’s shell.

The turtle’s shell was once vertebrae and ribs that eventually flattened then fused together. The shell serves to do more than protect the turtle from being bitten by other animals. During hibernation changes must occur in the way the turtle’s body works.

For example the process of burning fat becomes anaerobic or “without oxygen.” The process results in the accumulation of lactic acid. The shell stores acid and it also produces bicarbonates (basically baking soda to the acid’s vinegar) into the turtle’s body because too much acid is not a good thing.

Unlike most mammals, a turtle doesn’t have a lung and muscle combination because it doesn’t have ribs that would expand and contract around the lungs. Instead a turtle has muscles that pull its body out towards the openings of the shell so it can inhale. It has other muscles that compress the organs against its lungs to make it exhale. The effort is very costly in that every time the turtle uses those muscles its acid levels rise and its oxygen levels drop.

why do some turtles breathe through their anuses

Australian Fitzroy river turtle/Image: AngusMcNab

Why do some turtles breathe through their anuses? They breathe out their back ends because it’s easier. Near the turtle’s cloaca are sacs called bursa which easily expand. The sac walls are lined with blood vessels.

Sources state that oxygen “diffuses through the blood vessels and the sacs are squeezed out.” The process requires a minimal amount of energy and turtles don’t have a lot of excess energy anyway. Compare all the above mentioned effort to the fairly easy method of breathing out its butt.

Why do some turtles breathe through their anuses? They do so because it is much easier and because they can.

Why do some turtles breathe through their anuses? They do so because Nature or the Supreme Being of your choice has a sense of humor.

Why do some turtles breathe through their anuses? Now you know.

You ask the questions.  We provide the answers.

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About Will Phoenix

W. Scott Phoenix, B.A., B.S. was born in Hawaii, raised in Pennsylvania and resides in California. He has been a published writer since 1978. His work has appeared (under various names) in numerous places in print and online including Examiner.com. He is a single parent of three children and has also worked as an actor, singer and teacher. He has been employed by such publications as the Daily Collegian and the Los Angeles Times.