Have you got Amazon Prime?

Because if you've got it, you've got Amazon Music Prime.

All the music you love plus top podcasts add free included with Prime.

Got Prime, got Music, Amazon Music.

Download the Amazon Music app now to start listening.

This is Scientific American 60 Second Science.

I'm Ashley Pat.

You might say that Guillermo Ponds is a scientific monster hunter.

Even though he thinks that term, monster, never really captured his subjects right.

So they are regular animals that have gone through different developmental processes

that would end up building a body that is not what you expect.

What this researcher based in Madrid, Spain actually loves is the oddly amazing animals.

After all, he studies two headed worms.

We have these worms that are usually regular worms like with one head and one tail,

and that's normal, but sometimes they may have two heads or two tails.

And on the other side, there are worms which have one head and many tails always.

Officially, he looks at bifurcated anilids, meaning things like earthworms

that have come out of their larval stage with two heads,

or spontaneously sprouted two tails, or some other combination of mixed-up appendages.

We know that certain species, like some salamanders and insects,

have the ability to regrow appendages in a time of need.

But there's this one phylum of worms, the anilids,

...