The dinosaur extinction led to lots of new mammals and birds — and snakes to eat them

SARAH MCCAMMON, HOST:

Sixty-six million years ago, an asteroid shut the door on the dinosaurs. But it opened a window for other creatures to flourish, like mammals and birds, but also snakes.

MICHAEL GRUNDLER: Snakes essentially exploded in their ecological diversity.

AILSA CHANG, HOST:

That is Michael Grundler, a post-doctoral researcher at UCLA. He recently analyzed this frenzy of snake evolution, along with Professor Daniel Rabosky of the University of Michigan. Here's Rabosky.

DANIEL RABOSKY: They are almost as diverse as mammals, and yet they're sort of this big, missing piece in our understanding of how animal evolution and especially vertebrate evolution has unfolded in the past 100 million years.

MCCAMMON: Their study, out today in the journal PLOS Biology, provides a clue as to why snakes exploded in number. It wasn't just all the empty space the dinosaurs left behind. It was the snakes' ability to snack on an ever-expanding menu of different creatures.

RABOSKY: Snakes have sort of managed to do this remarkable evolutionary explosion in - of diets that you don't see in other groups of reptiles.

CHANG: Now, we don't know for sure how many kinds of snakes there were before the dinosaurs disappeared. But we do know there are about 4,000 species today, and they eat everything.

SARA RUANE: Lots of snakes love to eat other snakes. It's sort of the perfect shape and package, if you're a snake, to swallow right down.

MCCAMMON: Sara Ruane was not involved in the work. She is curator of herpetology at the Field Museum of Natural History in Chicago.

RUANE: There's snakes that specialize in eating things like scorpions and centipedes, in eating freshly molted crayfish, caterpillars. There's snakes that eat nothing but worms and slugs.

MCCAMMON: You get the idea. And essentially, those varied diets may be one reason for snakes' diversity today.

CHANG: As for that diversity, the study also dares to suggest that this post-dinosaur era that we are living in today - the Cenozoic Era - might need a new nickname.

RUANE: The Cenozoic is often referred to as the age of mammals because it's the time period in which mammals diversify at a really high rate. But the authors of this study point out, we could just as easily call the Cenozoic the Age of Snakes because almost all the same things happen. I'm going to start referring to it as the Age of Snakes. I'm totally stealing it because I think it's a great term.

MCCAMMON: It is a great term. It's official. We're now living in the Age of Snakes. So happy Thursday, everybody.

(SOUNDBITE OF TROUBLE SONG, "SNAKE EYES") Transcript provided by NPR, Copyright NPR.