Researchers at the Geology and Geophysics Department at Yale University decided to travel the snake family tree to find out how today’s snakes developed from their ancestors millions of years ago. What they found was that early snake ancestors likely had small rear legs, ankles and even little toes.
Finding Common Snake Ancestors
The comprehensive research by Allison Hsiang and colleagues is the first of its kind in the study of snakes and their evolution. In the search for snake ancestors, researchers examined various fossils and the anatomy and DNA of 73 types of lizards and snakes. They focused on finding the main snake and snake-like ancestor and the granddaddy of all present day snakes.
In their findings, recently published in BMC Evolutionary Biology journal, what the researchers learned is that snake ancestors likely had hind legs, lived in damp forested areas, evolved on land, not the ocean, and that they were nocturnal and ate soft-bodied prey no larger than themselves. Researchers feel that ancient snakes were only able to eat prey that was no larger than their own head and had teeth that were needlelike for grabbing prey. They were not able to constrict or handle prey that was larger than they were, unlike today’s boa constrictors and similar species.
It is believed they lived around 128-million years ago during the Early Cretaceous on the continent known as Laurasia. Laurasia covered the areas now known as North America, Asia, and Europe.
The ancestor of all current snakes evolved around 20-millions years afterward and lived on the Gondwana supercontinent, which is what Antarctica, Australia, South America and Africa used to be. The rise of snakes as a species occurred during what is called the Cretaceous Terrestrial Revolution. During that time, scientists believe there was a huge upswing of diversification of reptiles, insects and mammals.
Ability to Travel Aided Success of Snake Ancestors
Hsiang and her colleagues believe that snakes stopped being nocturnal when the earth started to cool and the nights became colder. This led snake ancestors to venture out more during the day. They believe that the family Colubroidae likely started the trend, as they are the family that covers over 85% of today’s snakes. It is felt that Colubroidae became so widespread because of its ability to adapt to activity during the daytime.
There are currently more than 3,400 species of snakes and the researchers believe that their success is partly due to their ability to travel. Snakes have the ability to travel in ranges of 42,500-square miles, which puts them in all kinds of different habitats. They have shown the ability to adapt to different surroundings from desert to water, living in arid areas and wet areas alike. This adaptability has impeded the spread of other types of land-based animals. The snake ancestors traveled around the world, adapting to where they ended up, giving us the great diversification of snakes we have today.
