Lizards are a kind of scale reptiles, which are widely distributed. There are more than 6000 species in all continents except Antarctica and most ocean island chains. This group is symbiotic because it excludes snakes that are also scaly.

Lizards usually have four foot feet and outer ears. Although some have no legs, snakes lack these two characteristics. Lizards and snakes share a movable square bone, which makes them different from those of sphenodonts with more primitive and solid skulls of bony monsters.

Lizards account for 60% of the existing non avian reptiles.

Lizards' tails usually have different colors than other parts of the body and are much more colorful to encourage potential predators to attack their tails first. Many lizards, including geckos and stone dragons, can shed parts of their tails through a process known as automatic slitting. This is an example of the pars proto principle, which sacrifices "a part of the whole" and is used by lizards to allow them to escape from predators.