Before we start tonight, thank you for being here.
This show exists for the parent, grandparent or grownup lying in the dark beside a child who's still full of questions.
If that's you, I'm really glad you found the show.
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Now, welcome to the Bedtime Scientist.
Something changes in late winter.
Not all at once.
Not in a way you'd notice right away.
The sun finds a new angle.
The air begins to loosen.
And deep in a mountain forest in Mexico, a butterfly wakes.
She's been here for months.
Folded against the cold, tucked close to millions of other monarchs hanging from the fir trees.
Their wings layered over the branches so thickly they look almost like bark orange and black all the way up into the canopy.
From far away, the whole forest looks like it's glowing.
But now, the light is changing.
And very slowly, very quietly, the wings begin to open.
She's a monarch butterfly, orange as a candle flame, edged in black, dotted in white along the borders of her wings.
With her wings wide open, she'd barely reach across your hand.
Here's the first thing that's worth knowing about her.
When she lands on a leaf, she can taste it through her feet.
Tiny nerve endings in her legs.
Tell her what the plant below her is made of, before her wings have even folded closed.
No hands, no tongue.
Her feet do the reading.
And then there's that orange.
It's not decoration.
When she was a caterpillar, she ate a plant called milkweed.
It's something that would make most animals very, very sick.
She held onto it, kept it in her body.
And now that warning lives in her color.
Every bird nearby learns what orange means.
Not because anyone told them.
Because they tried it once, and they remembered.
Her color is a message, and it works every time.
Now something inside her rises. quiet pull, a direction, north.
She carries kind of a compass, tuned to the light.
As the day moves, she reads the angles of the light against the hour and from that alone, with no map and no one to follow.
She knows which way to go.
But here's the part that might keep you thinking long after you close your eyes.
She tells time with her antennae, those two thin arms reaching from the top of her head.
They hold a living clock, one that tracks the movement of the day and feeds it directly to her inner compass.
Take the antennae away, and her navigation falls apart entirely.
With them, she never wavers.
And many researchers think monarchs carry one more guide.
The Earth's own pull.
An invisible current running through the ground, the rivers, far beneath the ocean floor.
A direction built into the planet.
One she was born knowing how to find.
One guide from the light above.
One from the world below.
And on both of them. heading north.
She won't finish the journey.
She'll travel for weeks, drinking nectar from early flowers, moving over wide fields, lifting off each morning when the light tells her keep going.
And then One day, she'll find what her body's been looking for.
Milkweed.
The only plant her children can eat.
She'll know it before she even lands, her legs reading the leaf the moment she touches down.
On the underside, Hidden from wind and rain, she'll lay her eggs.
And then, her part of the journey will be done.
Not the journey itself.
Just her part of it.
The eggs hatch into caterpillars.
They eat and grow.
When a caterpillar forms a chrysalis, that small, smooth, green case hanging from a branch, it doesn't just grow wings inside.
The tissues that made it a caterpillar begin to break down.
A different body takes shape from the inside.
Built in the dark, while the world outside goes on, with wind and rain and light.
For about two weeks, there's something in that green case, with no good name.
Not one thing, not the other, but in between, and becoming.
And then the wings open.
Orange.
Black.
White.
Ready to keep going.
They fly further north.
Their children do the same.
Then theirs.
Four generations moving through the warm months, until great-grandchildren she'll never meet reach the wide northern fields.
Long, bright days, milkweed growing in every direction, a whole long summer ahead of them.
She won't get there, won't see those fields, won't meet the ones who do.
But she goes first anyway.
Sometimes the journey is larger than the traveler.
For our monarch, it always has been.
Take another deep breath in.
Let it out.
Close your eyes and imagine the milkweed leaf in the early light of morning, pale in color, soft at the edges, and underneath it, Barely there, one tiny round egg, smaller than the period at the end of a long sentence and folded inside a living clock, a compass made of light, a pole from deep in the ground.
A warning written in orange.
And a journey that's been going on longer than anyone can remember.
Waiting to begin again.
That's how it's been every year.
The ones who wintered go first.
They travel as far as they're able.
They leave what they carried.
And what follows continues.
Not one butterfly making the whole trip, but a relay.
A long, living relay of wings and time.
And not one of them ever holds the whole thing in view.
Only the migration does.
And just before you drift off, to dream of one small egg beneath a milkweed leaf, waiting for the light to return.
I want you to know something about you.
Your mind is a wonderful thing, so full of curiosity.
And I like your mind, just the way it wonders.
I'll be back again soon to wonder more with you.
