Dr. Yara Haridi

It is completely different tissue.

And where did it come from?

That's such a good question.

So that's a whole section of study because we have fossils that look like they might have both.

Oh, yeah.

So so baleen whales came from toothy ancestors.

They came from whales that have teeth.

And so at some point they started losing one and gaining the other.

And that is quite like a controversial topic, because I think there's like one team that's like, no, they lost teeth first and then gained baleen.

And then another team says that there's an overlap there.

But yeah, so it just depends on how you're interpreting these like really middle fossils.

Do you think all that extra vascularity, all that extra blood supply around the lip of this certain fossil, is that because of baleen or is that just because maybe it had fleshy lips?

I don't know.

So yeah, that's a whole area.

People don't really know exactly how baleen evolved, but I think people are getting closer.

There's a lot of really cool new fossils in that time period.

I mean, so keratin is incredibly diverse tissue because our skin has keratin.

Our hair has keratin.

Our nails have.

So it can just be expressed anywhere, really.