Placeholder Image

Subtitles section Play video

  • 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.

  • Here's the inside of a turtle.

  • That's Maria Wojakowski, a biologist who's been studying turtle ecology for more than a decade.

  • Here's your shoulder girdle.

  • Here's your hip girdle.

  • 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.

  • You will see the lungs towards the top here.

  • 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.

  • They dig, like, really, really complex burrowing structures underground.

  • And of course, shells are incredibly useful for defense against predators, no matter how fierce they may be.

  • Turtles are amazing.

A turtle's shell is as much a part of its body as our rib cage is of ours.

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it