General Distribution
The chuckwalla is widely distributed throughout the Mojave and Colorado deserts from sea
level to 1250 m (4125 ft). It is found in a variety of desert woodland and scrub habitats but is
most frequently associated with, and reaches highest densities, in creosote communities. It is
restricted to areas with large rocks, boulder piles, or large rock outcrops on slopes, and less
frequently on flats. This lizard is active from mid-spring to mid-summer and occasionally in
fall. Densities of chuckwallas have ranged from 7 to 14 per ha (3 to 6 per ac) (Shaw 1939,
Stebbins 1954, Johnson 1965, Nagy 1971, Berry 1974). Habitat Requirements
This species requires rocky cover such as large rock outcrops, boulder piles or
scattered large rocks, usually on a slope but often on a flat (Stebbins 1954).
This lizard is found in a variety of habitats but most frequently, and in greatest
density, in creosote, exclusively in rocky areas. It is herbivorous and requires the presence of
perennial or annual plants, and rocks for shelter. Reproduction
Breeding occurs from April to June with a peak of activity in late April to
May. Clutch size ranges from 6-13, average 8 eggs. Females may produce one clutch in 2 or
3 years (Johnson 1965, Berry 1974). Daily/Seasonal Activity
This species can be active all year in warm areas, but most activity
occurs in spring and early summer (late March to July). Lizards bask on exposed rocks early
in the day, then forage or engage in social behavior. The hottest part of the day involves
basking or retreat into rock crevices. Afternoon activity may occur in mild weather. The peak
of foraging and reproductive activity is from late April to early June. This species is not
known to migrate. Diet and Foraging
The chuckwalla is herbivorous, feeding on flowers, fruits and leaves of creosote
and, to a lesser extent, on other perennials and annuals (Shaw 1939, Stebbins 1954, Berry
1974). Territoriality/Home Range
Home ranges of males averaged 1.9 ha (4.8 ac) and ranged from 1-3.3 ha
(2.5-8.3 ac); female ranges were smaller (Berry 1974). Males and females defend territories.
Males tolerate the presence of females in their territories (Berry 1974). Predator-Prey Relations
There are no reports of predation on this lizard but they are probably taken by
coyotes and other mammalian predators, larger avian predators, and possibly snakes. Literature Cited
Berry, K. H. 1974. The ecology and social behavior of the chuckwalla, Sauromalus obesus
obesus Baird. Univ. Calif. Publ. Zool. 101:1-60.
Johnson, C. R. 1965. An ecological study of the chuckwalla, Sauromalus obesus Baird, in
the western Mojave Desert. Am. Midl. Nat. 73:1-29.
Nagy, K. A. 1971. Seasonal metabolism of water, energy and electroytes in a field
population of desert lizards, Saurmalus obesus. Ph.D. Thesis, Univ. California,
Riverside.
Shaw, C. E. 1939. Food habits of the chuckwalla, Sauromalus obesus. Herpetologica
1:153.
Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill,
New York. 536pp.
Information gathered from California DFG - California Interagency Wildlife Task Group
