Snakes!

Lizards and snakes make up the largest order of the reptiles. Although we often think of them differently, snakes are basically legless lizards, from a biological perspective. Reptiles in this group are characterized by having scales or shields on their body and by having a lower jawbone that can be moved independently from the braincase. This allows snakes and lizards to open their mouths very wide, a trait that is especially noticeable when snakes, which also have a very flexible jaw, are eating relatively large food, as you can see below:

Besides the obvious lack of legs, snakes are distinguished from lizard by the lack of external ears. Snakes are all carnivorous, meaning they eat meat of other animals. Snakes frequently eat rodents, insects, eggs, and even other snakes. Almost all snakes lay eggs, and they generally abandon the eggs shortly after laying them.

The somewhat unusual body structure of snakes leads to some unusual characteristics. As was mentioned above, snakes have very flexible jaws. This helps make up for the fact that they cannot use limbs to grasp prey, like most animals do. Also, because their bodies are so long and narrow, if a snake has two of a certain organ, such as the kidney, they are found one in front of the other as opposed to side by side.

Only a small minority of snakes have venom. Of those that do, venom is usually used to immobilize and begin to digest prey, rather than as a means of self-defense. Nevertheless, snake bites can be both painful and dangerous, so it is always best to steer clear of snakes (as well as most other animals) in the wild. Snakes without venom usually kill prey by constricting, or wrapping their bodies around the prey and squeezing tightly.