Sauromalus ater


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Sauromalus ater
Species Authority: Duméril, 1856
Common Name/s:
English Common Chuckwalla, Northern Chuckwalla
Sauromalus obesus Baird, 1858
Taxonomic Notes: Hollingsworth (1998) examined variation in Sauromalus and concluded that five species should be recognized. He regarded S. obesus as conspecific with S. ater, and he used S. ater, which has priority, as the specific name of the combined taxon. No subspecies of S. ater were recognized. Based primarily on the extensive use of the name S. obesus, a petition to give that name precedence over that of S. ater was submitted to the ICZN. However, McDiarmid et al. (2002) questioned this reasoning and argued that the priority of S. ater should be maintained. In 2004, ICZN ruled that the name Sauromalus ater Duméril, 1856 has precedence over the name Sauromalus obesus (Baird, 1858) (Bulletin of Zoological Nomenclature 61: 74-75). Hence, Sauromalus obesus is no longer the correct name for the chuckwallas of the United States (or Mexico).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor/s: Hammerson, G.A.
Reviewer/s: Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

Geographic Range [top]

Range Description: This lizard occurs in the western United States and in northwestern Mexico. It ranges from southern Nevada, southern Utah, southeastern California, and western Arizona south to southern Baja California and west-central Sonora, Mexico; in Baja California, most of the distribution is away from the Pacific coast (Hollingsworth 1998, Grismer 2002, Stebbins 2003).
Mexico; United States
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species is represented by a large number of viable occurrences throughout the majority of the range in California, Arizona, and Sonora, Mexico. Abundance information is not available rangewide, but the total adult population size is probably more than 100,000. Coombs (1977) estimated a population size of 10,000-15,000 individuals in Washington County, Utah. The abundance in the remainder of the Utah range (Kane, Garfield, and San Juan counties) is likely to be less than in Washington County (G. Oliver pers. comm. 1998). Populations may vary with environmental conditions. According to Abts (1987), annual densities are variable with higher densities after relatively mild winters and the occurrence of summer rainfall. During a seven-year study in the Colorado Desert of southwestern California, densities ranged from 15 to 30 individuals per hectare (Abts 1987). Nevertheless, the area of occupancy and population size appear to be relatively stable over most of the range.
Population Trend: Stable

Habitat and Ecology [top]

Habitat and Ecology: This lizard inhabits rocky desert; lava flows, hillsides, and outcrops. Creosote bush occurs throughout most of the range (Stebbins 2003). Habitats encompass subtropical thornforest in the southern part of the range. Individuals seek shelter in rock crevices (or in burrows on islands in the Gulf of California; Grismer 2002). Eggs are laid underground.
Systems: Terrestrial

Threats [top]

Major Threat(s): Chuckwalla populations are locally threatened by excessive collecting and habitat degradation (New Mexico Department of Game and Fish 1997). Collectors not only remove individuals from the habitat which thus may reduce population viability but also often cause microhabitat destruction when tools are used to move or break rocks and exfoliations to expose the reptiles (New Mexico Department of Game and Fish 1997). Some subpopulations have been hard hit by collectors. For example, the easily accessible South Mountain subpopulation, near Phoenix, Arizona, has a unique colour pattern and is highly desired by the pet trade; exploitation of this subpopulation and destruction of its habitat are on the rise (Gergus et al. 1998). Historical populations in the Glen Canyon area of Utah have been reduced or eliminated by the damming of the Colorado River. Habitat degradation due to grazing activities of goats, sheep, and burros is also a potential threat. Overall, however, the species appears to be moderately to not very threatened across most of its range. The species is regarded as not very threatened in Sonora, Mexico (A. Villareal Lazarraga pers. comm. 1998).

Conservation Actions [top]

Conservation Actions: Habitat is protected from development in several national parks and monuments and in federal wilderness areas in the United States, and the species occurs within protected sites in Sonora, Mexico (A. Villareal Lazarraga pers. comm. 1998). Many sites outside formally protected areas are rugged and remote and thus protected from most potential threats.
Citation: Hammerson, G.A. 2007. Sauromalus ater. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <>. Downloaded on 21 April 2014.
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