The Fitzroy River turtle's ability to breathe through its cloaca

Evolution is basically a chaotic engineer, and the Fitzroy River turtle is its most creative project yet. While other reptiles have to constantly surface for air, this Australian local stays submerged for days by literally breathing through its backside.

It uses specialized sacs in its cloaca—the body's all-purpose exit—that are packed with tiny blood vessels. These act like internal gills, sucking oxygen directly out of the river water while the turtle naps on the bottom.

It is the ultimate survival hack for staying hidden from predators, even if it means your butt has to do the heavy lifting for your lungs.

Wait, does it have to 'twerk' to keep breathing down there?

Exactly! It’s not just a passive soak. To keep that oxygen flowing, the turtle has to muscularly pump water in and out of those cloacal sacs up to 60 times a minute.

Imagine doing a high-speed glute workout just to catch a breath while you're trying to nap. It sounds exhausting, but it’s the price this turtle pays for being the river’s ultimate hide-and-seek champion.

If the water stops moving, the oxygen supply dries up. So, while it looks like it's just chilling on the riverbed, its backside is doing rhythmic power-lifts to stay alive.

How much energy does that 'high-speed glute workout' actually burn?

Surprisingly little. While it looks like a frantic effort, it’s more like a low-power background app on your phone. The turtle’s metabolism is so slow that this rhythmic pumping is just a tiny blip in its daily energy budget.

It’s actually a massive energy saver. Swimming to the surface requires a huge burst of muscle power and exposes the turtle to predators. By staying put and 'twerking,' it burns fewer calories than a single trip to the top.

It’s evolution’s version of 'work smarter, not harder.' The turtle trades a constant, tiny effort for a safe, lazy life on the riverbed.

So, can this turtle just stay underwater forever then?

Not quite forever, but it’s the closest thing nature has to a living submarine. During the cold winter months, when its metabolism is basically on 'airplane mode,' it can stay submerged for weeks without a single gulp of surface air.

The catch is the water itself. If the river gets too warm or stagnant, there isn't enough dissolved oxygen for its backside to harvest. It’s like trying to breathe through a straw in a room with no ventilation—eventually, you’ve got to open a window.

So, while it’s a marathon champion of breath-holding, it still has to pop up occasionally to remind its actual lungs what oxygen tastes like, especially when the river environment gets a bit 'stuffy.'

Is surfacing actually dangerous, or just a minor inconvenience?

It’s a massive risk that could literally cost them their lives. Surfacing is the turtle’s 'walk of shame' because it’s forced to give up its best trait: being invisible.

Once it breaks the surface, it’s no longer a stealthy river-bottom ghost. It becomes a visible target for crocodiles and hungry birds. It’s a high-stakes trade-off: stay submerged and suffocate, or go up and risk becoming a snack.

This is why they cling to their butt-breathing. It’s not just about being lazy; it’s about staying off the menu for as long as turtley possible.