As with humans, snakes have evolved over time. They don’t use their legs as a mode of transportation. Their lineage traces back to a group of animals called reptiles called lizards. In the course of evolution, these lizards’ movement became less dependent on their legs.
Snakes and lizards are the members of the order Squamata. Lizards have fully developed legs that they use to move, while snakes prefer to slither. There is a lot of scientific disagreement as to why and how these species evolved in distinct ways. It’s safe to say that certain snakes still have the genetic code necessary to build legs and feet.
Until about 70 million years ago, a species of ancient snakes possessed hind limbs, according to recent findings by scientists. Reptiles like pythons and boas still have little hind legs that they use for mating purposes.
How come these snakes don’t have legs? It is because multiple genetic mutations that occurred over 100 million years ago have turned off the genetic makeup that drives this process. Let’s explore more about snakes with feet.
The Genetics behind this Mutation
The sonic hedgehog gene (SHH) is responsible for developing limbs, and over time, it has been damaged. For more than just limbs, the SHH gene is also essential for other purposes. For example, it also serves as a guide for organs and their positioning in growing animals. The SHH is active in lizards, resulting in legs and feet, whereas it is inactive in snakes.
What is the Exact Difference between Lizards and Snakes?
In Lizards, some genes can be “flipped on and off” throughout their growth period thanks to DNA sequencers called enhancers. A lizard’s four legs develop because the SHH requires the enhancers for proper limb development. In contrast, this enhancer has been mostly – but not entirely – omitted from snake DNA sequences over time. That is why a snake with feet is not a common sight.
Feet or Legs? What do snakes have?
A snake with feet is evidence that it descended from lizards, and lizards are known to have feet. So, despite the snake’s lack of a limb, it has toes.
What about Baby Snakes?
Femurs of snakes, as per a study published in the journal Current Biology, snake embryos develop limbs when they are just a few days old. A femur, tibia, and fibula were observed to begin development in embryos of pythons even in such a short period.
Can we call Lizards Snakes without Legs?
Ancestry is the key, but lizards without legs are not snakes. In addition, most lizards have eyelids and external ears, whereas serpents have not. The legs of many “legless” lizards, for example, are tiny vestigial limbs, while snakes have no external appendages at all.
What are Legless Lizards Called?
When most people think about a lizard with no legs, they think about a glass lizard. They’re named because their tails are so easily broken that they fall off. They break into smaller pieces like glass when they are smashed. All the glass lizards had either no legs or only a sliver of what they once had.
How many Legs do Pythons and Boas have?
For identifying and tracking purposes, snakes generally lack legs, although pythons and boas have two spurs on either side of the vent that serves as a remnant pelvic girdle and two legs.
What about Claws?
It is well known that pythons, boas, and kindred snakes have claw-like spurs on either side of their vents, according to Boulenger in “Catalogue of Snakes in the British Museum.”
What does it all mean? Some primitive snakes may be able to produce limbs with just a few genetic changes. Their DNA already contains the necessary components for this to happen; they’d need the appropriate circumstances to set them in motion.