From the tiny garter snake in your backyard to huge green anacondas, all modern snakes have evolved from those that survived the asteroid that wiped out the dinosaurs, a new study suggests.

There are around 3,700 species of snakes and they are found on every continent except Antarctica. With this kind of diversity, it’s easy to think that their origins can be traced back to when they started crawling on Earth over 100 million years ago, notes corresponding study author Nick Longrich. from the Milner Center for Evolution at the University of Bath. UK.

But new research reveals that today’s snakes evolved from much more recent ancestors.

The asteroid impact that happened 66 million years ago destroyed around 76% of all species, including non-avian dinosaurs. According to the authors, only a handful of snake species survived this Cretaceous-Paleogene event.

Longrich and his colleagues believe the event was a type of “creative destruction“. The surviving snakes were able to fill the voids created by their lost competitors.

“Creative destruction is how environmental disruption and extinction creates openings for things to evolve, which can replace – or even increase – biodiversity. It’s sort of the reverse of the creative destruction of economists, where building something new (eg cars) erases the old (eg horse-drawn carriages), ”Longrich told Treehugger.

“It’s possible that evolution is sort of moving into a rut – once all the niches are full, it’s hard for something new to happen – and rearranging things, sort of flipping over. the game board, it resets things and starts to turn things around like crazy again. ”

How some snakes survived

For their study, the researchers reconstructed the evolution of snakes using fossils and genetic analyzes to find the differences between modern snakes.

They discovered that all living snake species can only be traced back to a few species that survived the impact. The authors suggest that the snakes may have survived the impact and its dire effects because they are able to take shelter underground and exist for a long time without food.

“Snakes are good burrowers, and their burrows acted as natural fallout shelters, protecting them from the extreme heat of impact or the winter cold of impact,” says Longrich.

“Some snakes can eat subterranean invertebrates like termites, which probably weren’t affected by plant death. Other snakes can feed very rarely, taking large prey and going six months or even a few years without feeding. So when food was scarce, they could get by.

Because the asteroid event caused the extinction of so many of their competitors, including Cretaceous dinosaurs and snakes, the surviving snakes were able to move into new habitats, continents and niches, according to the researchers.

They have also started to diversify. According to the results, modern snakes, such as arboreal snakes, sea snakes, vipers and poisonous cobras, and constrictors, including boas and pythons, appeared after the asteroid event and the extinction of the dinosaurs. .

The results were published in the journal Nature Communications.

“It was a little surprising,” Longrich said of the results. “I had a hunch that we might find something like this with snakes, but these models are a little tricky. I would have guessed that the ancestor of boas, pythons and cobras lived in the Cretaceous, we found him afterwards, and all these lineages diverged thereafter.