
Adult on petroglyphs (Grapevine Canyon,
Lake Mead NRA) |
General Description: These are large, heavy bodied lizards. The body
color and tail color can be all black, black and white banded,
or all white, and chuckwallas can change from dark to light
depending on their body temperature. There can also be some rust
color. Chuckwallas are often confused with
Banded Gila Monsters, but chucks never have big patches of bright orange.
Taxonomy: Iguana Family (Iguanidae).
Technical Description: A large (total length 16 to 22 inches), heavy bodied lizard with loose
folds of skin around the head and neck. In males, the body color
generally is blackish with rust or reddish while the tail is unmarked
and light-colored. The females and young are blackish with light
crossbands on the body and tail. |

Adult male. Note the dark color and broad head. |
Diet: Primarily eats vegetation, especially leaves, flowers, and fruit. Young may eat insects and insect larvae.
Habitat: Rocky hillsides in the Mojave Desert Scrub habitat type. Found in Blackbrush, salt desert scrub, and Mesquite/Catclaw habitats. Typically found on rocky flats, rocky
slopes, and boulder outcrops. Requires shady, well-drained soil for
nests. |

Adult male. Note the large femoral pores and swollen base of the tail. |
Range: The species occurs throughout the southwestern deserts from southern Nevada and
southern Utah, southward into northwestern Mexico. This subspecies
occurs in southeastern California, southern Nevada, southeastern Utah,
and western Arizona. In southern Nevada, this species occurs on
virtually all undisturbed rocky hillsides up to about 6,100 ft in
elevation.
Breeding:
Similar Species: Chuckwallas often are misidentified as Gila Monsters,
the only other species of large, heavy-bodied lizard in southern Nevada. However, these two species can be separated by the presence of
large, black and orange scales on the Gila Monster. |

Juvenile (Valley of Fire, Nevada). |
Comments: To escape predators, chucks run into a deep crack, gulp air to inflate their
body, and wedge themselves into the crack. They may use their stout tail to
whip the hand of an approaching predator. These lizards were used as
food by native peoples. |
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Chuckwalla eat plant matter and make scat that is full of plant fibers. Chuckwalla scat can be seen around their favorite basking
rocks, so when you see chuck scat, look in the nearby cracks to see who is about. |
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