Lulu Miller

Incredibly quiet.

Like reptiles just don't make that much noise.

Oh, and it's believed that dinosaurs, which are huge overgrown reptiles, were also pretty silent.

Just imagine the movie is just like T-Rex being like, ooh, and then devouring people.

Oh, yeah.

But John says that's a thing.

Like, if you're only using your ribcage to make sounds... There's only so much air that you're, like, pushing out.

Exactly.

So what you have back then is just this relative silence.

But that all changes.

When a huge asteroid hits the Earth... Almost everything dies.

But crawling up from underground...

were the earliest mammals.

They were tiny.

They were like little mice.

Some of which had spent most of their lives climbing up trees, running from dinosaurs, burning up oxygen at an incredible rate.

And so they had evolved this really powerful muscle called the diaphragm that sits below the lungs that allowed them to take in air and push it out rapidly and powerfully.

This would kind of change everything.

Because even though you had these tiny little itty bitty mammals that had their tiny squeaks, over time as they evolved into bigger mammals with bigger lungs and bigger, more powerful diaphragms, you'd get bigger sounds, more air.

And John says at the same time, that valve, that slit in the throat.