Snakes and lizards both belong to the Squamata order. So why do lizards have fully formed legs while snakes are forced to move without them? Well, for one thing, some snakes can still develop legs and feet thanks to genetic coding they carry.
Most of them, however, have mutated over 100 million years ago and lost the ability to sprout limbs. Despite still carrying the coding in their bodies, it’s basically “switched off” so they don’t have any today.
The researchers from the University of Florida found that a gene called Sonic Hedgehog is responsible for limb development (yes, it was named by the video game character. They confirmed that there were once snakes with limbs but they have lost them over time.