Legless lizards: they look like snakes, but why they are attributed to lizards

Just looking at this creature is enough to understand that you have a snake. Smooth, long body, covered with scales, characteristic sliding movements and lack of legs. But do not make hasty conclusions. In fact, these are lizards that have no legs and look just like snakes. Why are they considered lizards?

It turns out that the absence of legs and the long spindle-shaped body of a reptile does not always mean that it belongs to a suborder of snakes. Among the lizards, there are several species that do not have legs and look little like their relatives. There is a family of legless lizards that include two modern species that live on the Pacific coast of North America.

The fact is that the absence or presence of legs is not the only criterion for biologists by which reptiles are classified as snakes or lizards. The legless lizards still had hints hidden from the observer that they once had legs. Representatives of this family have a shoulder girdle and shortened bones of the limbs, which are not externally visible, but can be traced only in the skeleton. And although there are some types of snakes that have the remains of the pelvic girdle, such a detail of the skeleton as the shoulder girdle does not exist.

And of course, do not forget about other anatomical features that distinguish representatives of snakes and lizards. This is primarily the structure of the eyes. The eyes of the lizards have eyelids, upper and lower, which are able to move, that is, these reptiles can blink. Snakes are deprived of this ability, since their eyelids in the process of evolution have fused with each other, forming a motionless film.

The structure of the jaws in these suborders also varies. Remember the shots of some documentary where an African snake swallows a huge ostrich egg, the diameter of which significantly exceeds the size of its head, or a boa constrictor, which caught a gaping beast in the jungle and swallows it whole, demonstrating the wonders of stretching its body. All these tricks are possible due to the special structure of the snake jaws having a movable connection. But lizards, including legless lizards, are not capable of this.

In addition to the above, snakes and lizards differ in the structure of the ears. Snakes have no outer and middle ear, and even no eardrum, while lizards have it, just like the middle ear.

In addition to a separate family of legless lizards, there are lizards from the spindle family, which are also deprived of legs, but possess all other signs of lizards. For example, in the European part of our country there is a coppice, or a fragile spindle, which also has no legs. Therefore, walking through the forest in search of mushrooms, do not be alarmed if you encounter such a reptile. This is not a snake, this is a real lizard, it’s just special.

Watch the video: The Difference Between Legless Lizards and Snakes (April 2024).