The Fitzroy River Turtle, native to Australia, is locally known as the "bum-breathing turtle." Why? Because when researchers observed this species in captivity, they were astonished to see sand and particles swishing about the turtles' tails. Upon closer inspection, the scientists discovered the Fitzroy turtles had two enlarged bursae that allowed them to acquire aquatic oxygen via the cloacal opening. Most turtles can acquire oxygen this way, incidentally. Bum-breathing allows them to extend their dive time.

By 2002, Toni E. Priest and Craig E. Franklin figured out that the Fitzroy turtle took bum-breathing to extreme levels. Common snapping turtles, for example, take in 4% of their oxygen through their cloacal bursae. In contrast, Fitzroy turtles use significantly more aquatic oxygen: 41% of their overall intake!

Cue the bad breath jokes now, you guys. For the record, this is what bum-breathing looks like: