There's no greater “out with the old, in with the new” than a mass extinction event. When the dinosaurs departed this Earth, it cleared the way for a vast array of mammals and birds to sprout forth from their ancestors. New research has found that this influx of species had a profound effect on snakes, who experienced an eruption of diversification in the absence of dinosaurs. Once confined to a diet of mostly insects, they began feasting on fish, birds, and even small mammals.
The new paper, published in the journal PLOS Biology, investigated how the K-Pg mass extinction event – which occurred 66 million years ago – changed the lives of snakes. Researchers assembled a dataset on snake diets made up of 34,060 observations of 882 species.
Using mathematical modeling, they were able to reconstruct a timeline of how snake diets changed following the K-Pg event, revealing that it was a time of enormous diversification. Starting at the common ancestor of extant snakes, a slithery character that gorged exclusively on insects, they moved through Earth’s history. They saw that as time went on, emerging snake species began incorporating novel prey items into their diet. Fish, birds, and mammals joined the insects as snake supper at a time when they themselves were experiencing growth and diversification.
"So impressive was the diversification of mammals that the Cenozoic is commonly referred to as the 'Age of Mammals'," the researchers wrote. "With nearly as many species of snakes as there are mammals, however, the Cenozoic might just as well be called the 'Age of Snakes'."
With new positions opening up in what the authors term the “ecospace”, these reptiles made like snakes and slithered into each one to occupy a new ecological niche, bringing with it fresh opportunities to chow down on the new arrivals – be they winged, warm, or wet. As the eruption of new opportunities plateaued over time, so too did their ecospace expansions, but as living snakes demonstrate, the resulting lifestyles from this diversification explosion were rich and delicious.
“Much of the stunning ecological diversity in snakes seems to result from evolutionary explosions triggered by ecological opportunity,” said study author Michael Grundler of the University of California in a statement.
“We find a major burst of snake diet diversification after the dinosaur extinction, and we also find that, when snakes arrive in new places, they often undergo similar bursts of dietary diversification.”
So, what’s on the menu, boyssssss?