Turtles can breathe with their butts, along with dragonfly nymphs and sea cucumbers.
But not all kinds of turtles can do that “trick”. Only some species of turtles can do that.
These species have developed ways to pick up oxygen even when submerged. They can nestle down underwater and slow their metabolism down so much they barely need any oxygen.
They can then take a small amount of water into their cloaca, which is the all-in-one opening reptiles have for defecation, urination, reproduction, and egg-laying. They can absorb the air in the water, then expel it and take in another small amount.
Generally turtles have amazing anaerobic capabilities, which allow them to survive on very little oxygen for prolonged periods of time. Like most reptiles, they do have lungs which take in air through the mouth and nose. But in particular species, there is a pair of sacs, or bursae that are connected to the internal portion of the cloacal opening, a single exit that acts as both the port for sexual reproduction and digestive system elimination.
One of these turtles is The Fitzroy River turtle, who can stay underwater, inhale water through the cloacal opening, and extract oxygen for its system. They also can breathe that way on land.
So, there you have it! Some turtles breathe through their butts!