Dr. Yara Haridi

So if you pet sharks one way, it's smooth.

But if you pet them the other way, it's super rough.

That sandpaper feeling you get from sharks is because they have little tiny teeth all in their skin.

Yeah, exactly.

merging into the hole.

Should we go back to the, what are they for on the outside?

So there's a couple floating hypotheses.

There's one that's like, okay, they're for protection because they're hard and they're on the outside.

And at that time period, middle Ordovician, there's like big scary things in the ocean, big cephalopods, so big squid nautiloid looking things that,

would eat our little fishy ancestors.

There's big sea scorpions that are bigger than you or I that are up to like six feet or more.

Again, things that would eat our little fishy ancestors.

So it makes sense that the first hypothesis was protection.

Another one that's based more on sharks is that maybe it helps them with locomotion.

So when I said these fish are really weird looking, they don't have fins yet.

So the first ones didn't have pectoral fins.

They just had a tail.

It's like a tube.

Like I said, it's a handheld vacuum with eyes on the end and an open mouth.

So how do they move around in these like turbulent seas?