Hard as it may be for us to imagine a snake that doesn’t slither, scientists have discovered that the ancient ancestors of snakes walked the Earth with two small hind legs, complete with toes and ankles.
A team of paleontologists from Yale University set out to investigate how modern snakes came into being, when and where they originated.
For the study, the researchers analyzed 73 species of living snakes and lizard, comparing their fossils, genetic sequencing and anatomical structures. They ended up putting together what is known as the most comprehensive snake “family tree” we’ve seen so far.
Daniel J. Field, study author and doctoral candidate in evolutionary biology, and his team of experts identified 11 characteristics that that they wanted to include into the snake’s tree of life.
Each of the 11 traits served to answer a question that scientists often debated – did ancient snakes used to dwell in the water or on land? Did they originate from the Northern or the Southern Hemisphere? Did they ambush their prey or forage for food?
Field gave a statement revealing that “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”.
He goes on to add that the snakes’ ancestors first evolved on land, not in the sea. They lived in forests, and the very first specimens are believed to have originated in the Southern Hemisphere, roughly 128.5 million years ago.
The dinosaur-snakes were nocturnal predators (and some modern snakes still are) that did not crush their prey with their bodies, but rather used a set of very sharp, hooked-shaped teeth to devour it whole.
While they did not shy away from a fight with fairly large animals, they weren’t quite able to take down super-big prey that many modern-day snakes have no trouble defeating. This is exactly because modern snakes rely heavily on constriction as a form of attack, boas and pythons in particular are known for it.
Diurnal snakes are believed to have originated about 45-50 million years ago. The theory is that low night temperatures are what caused the Colubroidea family of snakes to evolve to hunt during the day.
Allison Hsiang, study co-author and Yale University professor, felt it was important to mention that while snake origins have been debated for a very long time, this is the first time that these hypotheses have been tested thoroughly using cutting-edge methods.
Jacques Gauthier, University professor, was especially intrigued by the study as human beings have a natural and adaptive attention to snakes, which brings up a lot of questions related to their evolutionary origin and their prehistorical relationship to us as a species. Interestingly enough, the emergence of snakes coincides with that of most mammals and birds.
The scientists theorized that snakes lost their small, hind-side legs due to them getting in the way of reptiles’ slithering, however vestiges of their existence still remain within many species of snakes. J. Field was amazed at how strongly scientists inferred that the common ancestor retained hind limbs.
The study, published in the journal BMC Evolutionary Biology, mentioned that so far, researchers know of no common ancestor of all living snakes that also had forelimbs in addition to the small hind legs.
There are currently more than 3.400 species of snakes living on the planet. Most of them are known for their beautiful skin patterns, beautiful colors, agility and ferociousness.
Image Source: dailymail.co.uk