Description: Sonoran spiny-tailed iguana are predominantly black, but their dorsal surfaces may show black bands on a grayish background. Most have black mottling on their backs. The color may also lighten after basking in the sunlight, with yellowish and orange markings becoming evident along the sides. Their tails are ringed with rows of sharp, curved spines.

Habitat: The Sonoran Spiny-tailed Iguana inhabits desert areas, foothills, and seasonally-dry tropical lowlands. The probable distribution area includes climate classifications of: 1) warm/semi-warm and sub-humid, 2) a semi-arid, steppe climate, 3) arid, semi-arid, and very arid, and 4) sub-humid temperate. They live in tree trunks, within cacti holes, and rocky cliffs. In suburban areas and towns they can use rock piles, fence holes, brick holes, and spaces between walls as retreats. They tend to forage very close to their retreats.

Range: The Sonoran Spiny-tailed Iguana is endemic to the Sonoran desert. This species is found in the Mexican states of Sonora, Sinaloa, and southwestern Chihuahua, from Benjamín Hill, Sonora, in the north, to El Limón de los Ramos, Sinaloa, in the south (Rorabaugh et al. 2015). They can be found near sea level on the Gulf of California and inland on the western side of the Sierra Madre Occidental mountains, as far east at Santa Ana, Chihuahua. This latter area comprises desert, mountains, and dry tropical forest and is not well explored. Introduced into Arizona, which apparently was brought from adjacent Sonora in Mexico.

Found in these States: AZ

Diet: This iguana is omnivorous, with a heavily insectivorous diet as juveniles, but all age classes are known to eat ants and termites, as well as leaves, cacti, and fruit

Reproduction: Like most species of Ctenosaura, the Sonoran Spiny-tailed Iguana has a short breeding season in the driest part of the year, and likely reproduces annually. There is geographic variation in reproduction; females in Chihuahua have large follicles in July, whereas males and females in Sinaloa and Sonora appear to be reproductive starting in April and are finished by June. Females may lay up to 12 eggs.

Status: The Sonoran Spiny-tailed Iguana is widely, but unevenly distributed in Sonora, Sinaloa, and a small portion of southwestern Chihuahua, México. In this area, 29% of their habitat has been converted to large- and small-scale agricultural, ranching, and urban uses. It is suspected that there has been a rate of loss in the iguana population correlated to this habitat loss; 20% of this loss occurred more than three generations ago. The population seems to be structured in small, isolated subpopulations, with large concentrations in some areas and absent in others. There are no data available on the population size, trend, or density at any locality. They are able to exist in mildly human-impacted areas, such as the peripheries of crop/ranchlands and suburban areas, however, here they are more vulnerable to predation by free-ranging and feral cats and dogs. Survival of juveniles may be limited as a result. In some regions iguanas are persecuted as a pest, while in others they are not intentionally harmed and can be found in city gardens. Hunting for human food occurs mostly for celebrations and is declining according to local interviews. There are no quantitative data on the level of this take. At the southern end of their range, these iguanas are declining in number as they hybridize with the resident Guerreran Spiny-tailed Iguana (Ctenosaura pectinata). Currently, they are considered Least Concern, but further research on the population size, trends, and threats is needed.

Taxonomy: