The western fence lizard is a common lizard of Arizona, New Mexico, California, Idaho, Nevada, Oregon, Utah, Washington, Northern Mexico, and the surrounding area. As the ventral abdomen of an adult is characteristically blue, it is also known as the blue-belly.

The eastern fence lizard is a medium-sized species of lizard in the family Phrynosomatidae. The species is found along forest edges, rock piles, and rotting logs or stumps in the eastern United States. It is sometimes referred to as the prairie lizard, fence swift, gray lizard, gravid lizard, northern fence lizard or pine lizard. It is also referred to colloquially as the horn-billed lizard. One of its most notable behaviors is that of its escape behavior when encountering fire ants, which have been known to invade and negatively affect many of their populations.