Hold Onto Your Butts
Especially if you're a turtle.
Hi, I’m Joey! Welcome to Fun Fact Friyay, the newsletter for curious people. This one might get your booty shaking.
Today’s fact: Fitzroy River turtles breathe out of their butts.
When I was in high school, my family took a trip to the Galapagos Islands. I remember spending a ton of time just watching native turtles and tortoises munching on leaves, an oddly soothing experience.
Then, in college, I studied abroad in China and during a visit to a local garden, I paused for probably 30 minutes glued to the edge of my seat—which was the ground, because I was standing—as a turtle tried to climb from a pond up the side of a rock to bask in the sun.
The turtle got 95% of the way there before slipping and tumbling back down into the water. But I’ll be darned if that turtle didn’t start making another attempt. That’s the kind of perseverance that inspires us.
What I didn’t notice was how any of those turtles were breathing. If I had been in Australia, the answer may have been “through their butts.”
Through a fancy-sounding phrase called cloacal respiration, Fitzroy River turtles (native to Queensland, Australia) take oxygen in and push carbon dioxide out. And that main source of oxygen comes via their booties.
Turtles are cold-blooded, so as the weather gets colder in the winter, a turtle’s internal temperature and metabolism both drop accordingly.
As a result, turtles can survive entirely by diffusing oxygen from water passing over them. For Fitzroy River turtles, that process happens through their butts.
There are likely a few other side-necked turtles that also use cloacal respiration, especially during deep dives in water. But the Fitzroy is the most popular, with up to 68% of its oxygen intake occurring through the cloacal bursae.
Turtles as a species are quite the impressive breathers. Some have survived up to 33 hours in an atmosphere made entirely of nitrogen and no oxygen. That’s nearly a day and a half!
Can you imagine holding your breath for 33 hours? Even if all turtles can’t breathe through their butts, I’m still impressed by their anaerobic capacity.
It’s like we’ve always heard: Slow and steady wins the breathing contest.