You're listening to Shortwave from NPR.

Hey Shortwaveers, Regina Barber here with Shortwave First Timer, Kiara Eisner,

a reporter on NPR's Investigations Unit. Hey Kiara, hey Regina!

So for this first story, I want to take you back millions of years.

Let's do it. Hundreds of millions of years before dinosaurs roamed the planet.

Horseshoe crabs are one of the few animal species that have survived

all five of the major mass extinctions that have happened on planet Earth.

I love Horseshoe crabs. There are these prehistoric animals that look like stingray,

shaped crabs, and they can live up to 30 years.

They spend most of their lives at the bottom of the ocean.

Yes, and once a year, though, they come up from the bottom onto the beaches to mate.

They mate in these giant mounds all along the Atlantic coast.

And migratory shorebirds come from the south of the globe.

They fly north, and they stop along the same beaches,

because some of them want to eat the eggs of the Horseshoe crab.

But humans want something from the crabs, too, and that's their blood.

Yeah, so we take Horseshoe crabs from the ocean for their blood,

which is sky blue, by the way, because scientists discovered that that blood would clot

when it detected bacterial toxins.

Yeah, I've heard that they're used in the medical field.

Is that right?

Yes, so vaccines, drugs, medical devices, anything that's put directly into the human body,

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