Welcome to Brain Stuff, a production of IHeartRadio.

Hey, Brain Stuff, Lauren Vogelbaum here.

According to the prevailing scientific theory, non-avian dinosaurs met their dramatic end

after an enormous asteroid hit the Earth near what's now Mexico, about 66 million years ago,

give or take.

This mass extinction, known today as the Cretaceous Paleogene or the Cretaceous tertiary

extinction event, caused a huge amount of debris like dust and ash to fill the atmosphere.

This, in turn, created what's called an impact winter,

in which life-giving light from the sun was blocked. A plant life couldn't photosynthesize and

thus died off. The ocean acidified, the food chain was disrupted, and some 70 to 80% of all

life on the planet was wiped out. It was the literal end of an era, the Mesozoic, to be specific.

The mighty non-avian dinosaurs were perhaps the most famous of the life forms that died out post-astroid,

but many others became extinct as well. These included aquatic reptiles like Pleasiosaurus,

the first vertebrate animals to fly by flapping their wings, the pterosaurs,

vast numbers of oceanic invertebrates, and some 90% of algae species. Life was never the same.

But some types of animals weren't hit nearly as hard. At least a few members of about 84% of marine families

and 82% of land vertebrate families made it through. So many life forms survived the event that it would

take way more than a podcast episode to describe them all. And many of the animals have descendants that

still live today. Some of these species look a lot like their Mesozoic counterparts. Others have

changed quite a bit, including birds, which are the descendants of avian dinosaurs that managed to

survive the extinction event. So aside from birds, which of today's animals walked, crawled, slithered, or swam alongside dinosaurs?

Dinos lived on Earth during the Mesozoic era, which lasted from 248 to 66 million years ago.

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