Lizards are reptiles typically characterized by the following features: four legs, movable eyelids, scales along the sides and underside of the body, a long detachable tail, and a lower jaw with a rigid skeletal structure. Although some species of lizards, such as the glass snake (top, center), lack external legs, they are still classified as lizards since they possess movable eyelids and a lower jaw that does not separate when swallowing large food items. Pictured here are (top, left to right) the chameleon, glass snake, monitor, (bottom) iguana, Gila monster, and gecko.

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