A previous scientific name used for the chuckwalla is Sauromalus obesus. A male individual can measure up to 18 inches in total length, while the female is somewhat smaller. The coloration of these lizards is geographically variable and also varies between juveniles and adults, in addition to males and females. In adult males, the head, shoulder, and pelvic regions are melanistic, while the mid-body is light beige or tan and occassionally speckled with brown flecks. The tail is off-white.
Adult females are brownish in color with a scattering of dark brown and red spots.
Young chuckwallas have four or five broad bands across the body, and three or four on the tail. These bands are usually lost in adulthood. Uniformly small scales cover the body, with larger scales protecting the ear openings. Often we see them waddling along, then suddenly leaping from rock to rock. One that I found eating flowers in an encelia bush suddenly dropped down and took refuge in a rock crevice.