Asked by: Rob Banino, Bristol
It’s thought that snakes lost their legs 100 to 150 million years ago, but debate is still raging as to whether their limbed ancestors were aquatic or terrestrial.
The evolution of a long, legless body could be beneficial to life underwater as it would enable eel-like swimming. But it could also be beneficial on land, making burrowing and hunting underground easier.
Either way, we can still see traces of their legs today: boas and pythons, the most ancient surviving snakes, have tiny leg bones buried in the muscles towards their tail. The more advanced snakes, however, have lost them completely.