Snakes Have No Legs Because of a Mutated Sonic Hedgehog Gene EnhancerRhett JonesSunday 4:01pm856EditPromoteDismissUndismissHideGo to permalinkSnakes! Where are their arms and legs? It’s not ok! Over 100 million years ago, snakes did have four appendages, and then evolution stepped in to turn the reptiles into the creepy, slithering freak show that they are today. Now, researchers believe they’ve isolated what caused this change.