They are sexually dimorphic with males having reddish-pink to orange, yellow or light gray bodies and black heads, shoulders and limbs; females and the immature have bodies with scattered spots or contrasting bands of light and dark in shades of gray or yellow. Males are generally larger than females. Males also posess well-developed femoral pores located on the inner sides of their thighs; these pores produce secretions believed to play a role in marking territory.
The other species are island-dwelling and therefore have much more restricted distributions: Two rare and endangered species are the Montserrat chuckwalla (Sauromalus slevini) found on Islas Carmen, Coronados and Montserrat in the southern Gulf of California and the San Esteban chuckwalla or Painted chuckwalla (Sauromalus varius) found on San Esteban Island, Lobos and Pelicanos.
The Angel Island chuckwalla (Sauromalus hispidus) and peninsular chuckwalla (Sauromalus australis) are found on Isla Ángel de la Guarda and surrounding islands off the coast of the Baja California peninsula.
Chuckwallas prefer lava flows and rocky areas, and many more such as those found in the Sonoran and Mojave Deserts. These areas are typically vegetated by creosote bush and other such drought-tolerant scrub. The lizards may be found at elevations of up to 4,500 feet (1,370 metres).
Primarily herbivorous, chuckwallas feed on leaves, fruit and flowers of annuals and perennial plants; insects represent a supplementary prey. The lizards are said to prefer yellow flowers, such as those of the brittlebush (Encelia farinosa).
Males are seasonally and conditionally territorial; an abundance of resources tends to create a hierarchy based on size, with one large male dominating the area's smaller males. Chuckwallas use a combination of colour and physical displays, namely "push ups", head-hobbing, and gaping of the mouth to communicate and defend their territory (see animal communication).
Chuckwallas are diurnal animals and as they are exothermic, spend much of their mornings and winter days basking. These lizards are well adapted to desert conditions; they are active at temperatures of up to 102°F (39°C). Chuckwallas hibernate during cooler months and emerge in February.
Mating occurs from April to July, with 5-16 eggs laid between June and August. The eggs hatch in late September. Chuckwallas may live for 25 years or more.