A new study by researchers at Yale University found that the ancestors of modern snakes likely had no forelimbs, but did have hind legs. This is not especially surprising since scientists have long believed that snakes evolved from ancient lizards, but researchers say the new discovery has resolved many age-old debates on the origins of snakes.
“We generated the first comprehensive reconstruction of what the ancestral snake was like,” Allison Hsiang, lead author of the study, said in a press release from Yale. “We infer that the most recent common ancestor of all snakes was a nocturnal, stealth-hunting predator targeting relatively large prey, and most likely would have lived in forested ecosystems in the Southern Hemisphere,”
That common ancestor lived more than 128 million years ago in the Early Cretaceous. Back then, early snakes had not yet developed the anatomy to constrict prey, but instead held onto its food with tiny, sharp teeth and swallowed them whole. According to the study, which was published in the latest edition of the journal BMC Evolutionary Biology, these snakes evolved on land, not water.
“Our analyses suggest that the most recent common ancestor of all living snakes would have already lost its forelimbs, but would still have had tiny hind limbs, with complete ankles and toes,” said co-author Daniel Field.
What purpose did these tiny limbs serve? The study suggests that the legs may just be evolutionary remnants as snakes developed smaller and smaller limbs to suit a burrowing lifestyle. You can see an artist’s representation of early snakes below: