Monarch butterflies make one of the most extraordinary migrations in the natural world,

often traveling thousands of miles across North America.

Now, scientists are using new tracking technology to get a greater understanding of those journeys.

Ali Rogan spoke with Dan Fagan.

He's a Pulitzer Prize-winning journalist who teaches science journalism at New York University

and is writing a book about monarch butterflies.

Thank you so much for joining us.

Dan, I have to be honest, I wasn't aware

of the complicated and long journeys

that these monarch butterflies take when they migrate.

So tell us about their migration patterns.

Yeah, it's it's kind of amazing what they do. They live one way during the warm weather months when those of us in the US are more familiar with them.

But when the weather gets cooler, they change. Instead of just living a few weeks, they live the whole winter, at least if they're fortunate

enough to survive, they live the whole winter.

And they undertake this amazing migration.

For monarchs in the eastern US, they go to Mexico, and for monarchs in the west, west of the Rockies, they go to the California coast.

And they go there because they are very weather sensitive. They can't survive if it's too cold or if it's too hot.

So they have found these havens where they can safely over winter,

and that's what they do every year.

And you've written about these new tiny sensors that scientists have created

to be able to track individual butterflies.

How does this work?

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