Michael Levin

So they do not age.

There's no such thing as an old planarian.

So that right there tells you that these theories of thermodynamic limitations on lifespan are wrong.

It's not that well over time everything degrades.

No, planaria can keep it going for probably, you know, how long have they been around?

400 million years, right?

So these are the actual, so the planaria in our lab are actually in physical continuity with planaria that were here 400 million years ago.

Because what they do is they split in half.

The way they reproduce is they split in half.

So the planaria, the back end grabs the petri dish, the front end takes off, and they rip themselves in half.

Yes, except that we go through a bottleneck of one cell, which is the egg.

They do not.

I mean, they can.

There are certain planaria that... Got it.

Yes, like an autoencoder, you know, square.

washed down to one cell and then back out.

These guys just tear themselves in half.

And so the other amazing thing about them is they regenerate.

So you can cut them into pieces.

The record is, I think, 276 or something like that by Thomas Hunt Morgan.