Hey, it's Flora, and you are listening to Science Friday. A scientific mystery right under your nose. Yawning. Almost every animal with a backbone does it. Hopefully you are not doing it right now as you listen to this show. And here's the thing. It actually remains a mystery

exactly why we yawn. But a listener awakened us to some new research that offers up some clues.

Hello, my name is Eileen. I'm from Houston, Texas, and I saw some new findings about yawning

and something about maybe whenever people yawns,

the blood goes from the, like to the brain or from the brain or something.

Could you clarify that?

It sounds pretty fascinating to me.

Yes, Eileen, we can clarify that.

On the line with us right now is the scientist who led that

research, biomechanical engineer, Dr. Lynn Bilston at the University of New South Wales in Sydney.

She studies how mechanical forces in the body affect her health. Welcome to the show.

Thank you, Flores. Lovely to be here.

Okay, so why focus on yawning?

So we were doing some other research at the time that was looking at how breathing

affects the flow of the fluid that sits around your brain and spine cord.

And I had a student who was particularly interested in yawning, and we put the two of them together and thought that

since the breathing really changes that fluid flow, that perhaps yawning also will affect that

fluid flow of the cerebrospinal fluid, as we call it, around the brain and spinal cord.

That's where this all started.

What does this fluid do?

So cerebrospinal fluid, or CSF for short,

is the fluid that your brain and spinal cord kind of float in. So it has two main functions. The first

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