Legless, often carnivorous reptiles that can be distinguished from legless lizards by the lack of eyelids and external ears: Many species of serpentiforms have skulls with more joints than their lizard ancestors, which enable them to swallow prey much larger than their heads with their highly movable jaws.

Most species serpentiforms are nonvenomous and those that do have venom use it primarily to kill and subdue prey more than for self-defense. Some possess venom potent enough to cause painful injury or death to humans.

Nonvenomous serpentiforms either swallow their prey alive or kill them by constriction in which it initially strikes at its prey and holds on to it, pulling the victim into its coils or, in the case of very large prey, pulling itself onto the creature; then the serpentiform will wrap one or two coils around the captured animal.