This is Origin Stories, the Leaky Foundation podcast.

I'm Meredith Johnson.

Today on the show, we'll meet a Leaky Foundation grantee who uses clues locked inside fossil teeth to tell stories about

the lives of our prehistoric relatives and the world they lived in.

I can use my big room voice if you want.

Back when it was possible to do interviews in person, I sat down with Leaky Foundation grantee,

Dr. Tanya Smith.

Sure. My name is Professor Tanya Smith. I work at the Australian Research Center for

Human Evolution at Griffith University. She's a paleoanthropologist whose specialty is teeth.

She focuses on what teeth can tell us about human growth and development, behavior, and evolution.

And she's the author of the book The Tales Teeth Tell.

Lots of people know about tree rings. When you saw open a tree trunk and look inside, you can see

these beautiful rings that record each year of the tree's growth. What you might not know

is that your teeth also record time, in layers of growth that form

tiny lines on a much finer scale than trees do.

From before you were born until the day you die, your teeth record your life story

without you even knowing it.

The days, weeks, seasons, and years are locked inside our mouths in microscopic timelines.

Tanya is an expert at reading these tiny timelines in our teeth.

So I really do on a good day when I can get a couple hours in the lab, turn off the lights,

put on some good music, and sit on a microscope, and I count lines and teeth.

And I measure little daily increments.

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