A large, flat, dark-bodied lizard, 3-4 inches, with loose folds of skin on neck and sides. Tail with blunt tip and broad base. In southern Utah, adults keep juvenile dark crossbars on tail. Often seen sprawled on rocky outcrops in sun. When disturbed, puffs itself up by gulping air and wedges tightly in a rock crevice. Found near creosote bushes on rocky hillsides, outcrops and lava flows. Eats a variety of desert plants and occasionally insects.