[Narrator] A turtle's shell
is as much a part of its body as our rib cage is of ours. In fact, it is their rib cage, and their spine, and their vertebrae, and their sternum. Basically, a turtle's
skeleton is inside out. And just like you can't take a skeleton out of a person, right,
you can't take a turtle out of its shell either. But if you could, you'd probably be surprised
by what you'd discover. Maria Wojakowski: Here's
the inside of a turtle. [Narrator] That's Maria Wojakowski, a biologist who's been
studying turtle ecology for more than a decade. Wojakowski: Here's your shoulder girdle. Here's your hip girdle. [Narrator] Notice how
those hips and shoulders are actually inside the turtle's rib cage? Turtles are one of the only
land animals on the planet with this feature. They're also some of the
only animals that can breathe with their butts. You see, inside a turtle shell is a very particular respiratory system. Wojakowski: You will see the
lungs towards the top here. [Narrator] Now, most land animals breathe by expanding and contracting their ribs, which creates a natural
pump that guides air in and out of their lungs. But turtles can't do this because their rigid shells don't expand. So instead they rely on sheets of muscles within their shell to pump in
oxygen through their mouths. That is, most of the time. Then there are other times when turtles breathe out the other end, more specifically, through what
scientists call the cloaca. It's the same opening that
turtles use to urinate, defecate, and lay eggs. And in some cases, it can
double as a set of gills, sucking in water and
absorbing the oxygen within. Scientists think that turtles do this when they're spending long
periods of time underwater, like when they're hibernating. And if you look really closely
at the inside of a shell, you'd discover another feature that helps with hibernating underwater: a scaffold-like structure that can store and release chemicals. That structure actually
helps turtles breathe without any oxygen at all. It works like this: Many turtles hibernate in frozen ponds that are starved of oxygen, and to survive, their
metabolism switches over from aerobic to anaerobic. That means they stop
using oxygen for energy and start using glucose instead via a process called
anaerobic respiration. And the byproduct of that is lactic acid. Now, theoretically,
this acid could build up in a turtle's body and kill it. That's where the shell's
structure comes in. It can absorb the lactic acid as well as release a bicarbonate
to neutralize that acid. It's essentially Tums, but for turtles. So as it turns out, having
a shell is pretty handy for certain situations. In fact, scientists think that turtles originally got their shells for digging, likely more than 200 million years ago. Wojakowski: They dig, like,
really, really complex burrowing structures underground. [Narrator] And of course,
shells are incredibly useful for defense against predators, no matter how fierce they may be. Turtles are amazing.
“Stop using oxygen for energy and use glucose instead” Okay dude
Well I learned something new today and I really enjoyed it. Turtle power 🤣🤣🤣👍
we had a tortoise for 25 yrs and I had no idea about this! I am not surprised that they can breathe thru their butts, tho. Our tortoise made crazy loud noises sometimes that sounds like a horn and the vet told us it was coming from its butt and was no big deal.
That’s really awesome! I had no idea. You should try posting this over at r/unseennature. I think that audience would enjoy it. Thanks!
I mean a turtle had a stand, 「SILVER CHARIOT」so trust me they get even more special, unexpectedly.
Freaking love turtles
The cloaca doesn’t actually “suck in air”, isn’t it used to absorb oxygen through diffusion when under water? That’s what I was always taught...
Wow! That was great. Very informative.
I want a cloaca!!