Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years. Yacold also

partners with nature portfolio to advance gut microbiome science through the global grants for

gut health, an investigator-led research program. To learn more about Yachtold, visit yawcult.co.

.jp. That's Y-A-K-U-L-T.co.jp. When it comes to a guide for your gut, count on Yacult.

This is Scientific American 60-second science. I'm Bob Herschon.

Most animals are pretty good at avoiding the embarrassing faux-pa of having sex with the wrong species.

But what if you're a millipede under a cramped, dark, slippery rock,

with a dozen or more species all scurrying about looking for love?

Fortunately, the critters evolved a solution, elaborate male gonopods, literally genital feet, with all manner of branches, bumps, and bristles.

And even with 12,000 species of millipedes, no two varieties of gonopods are exactly the same.

So the little arthropods could immediately tell if they're consorting with the wrong species.

Convenient not only for the millipedes, but also for biologists.

So you just have to pick it up and look at it, and you see,

oh, yes, that's the species and you can identify it.

That's millipede researcher Petra Cyrvald at the Field Museum in Chicago.

The only problem is, no offense to any male millipedes, the gonopods are tiny.

If you look at a millipede, it's not that big to begin with, so you can imagine their modified

legs are even smaller.

Now before we go any further, you might be wondering,

who cares about millipedes, let alone their genitals? And the answer is not enough of us.

Millipedes are believed to be the first land animals, lured out of the water by tasty dead

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