Animals
Can turtles really breathe through their butts?
The short answer
Some can. Several freshwater turtles absorb oxygen through the lining of the cloaca. The Fitzroy River turtle of Australia does it well enough to meet effectively all of its oxygen needs this way, letting it stay submerged for extraordinarily long stretches.
The cloaca is a single multipurpose opening handling waste and reproduction. In some turtles it does one more job. Water is pumped in and out of two sac-like organs called bursae, lined with fine papillae that carry a dense blood supply. Oxygen diffuses across them straight into the bloodstream — gills, more or less, in an unexpected location.
The Fitzroy River turtle, Rheodytes leukops, is the standout. It can meet effectively all of its oxygen requirements through cloacal respiration, which is why Australians call these species bum-breathing turtles without a hint of embarrassment.
It matters more than it sounds. Being able to stay down means not surfacing, and not surfacing means not being seen by predators — and, for turtles hibernating under ice, it means surviving a winter with the lid on.
Sources
- Can turtles really breathe through their butts?Live Science
- Mary River TurtleThe Australian Museum