Description: C. pectinata has distinctive keeled scales on its long tail, to which its common name refers. It is one of the larger members of the genus Ctenosaura, capable of growing to 4.3 feet in total length (including tail), with females being slightly smaller than males at 3.3 feet. It is usually brown or grey-brown in coloration dorsally, with a yellowish ventral surface. It has a crest of long spines which extend down the center of its back. Hatchlings are often a bright green color with no body pattern, and darken as they age.

Ctenosaura pectinata often (but not always) has an irregular piebald pattern on the head or dorsal areas. Although the tail may be banded with light and dark crossbands, C. pectinatatypically lacks a clear or well developed crossband pattern on the body, which is often present in the similar appearing and closely related species Ctenosaura similis and Ctenosaura acanthura. Ctenosaura pectinata varies from gray to a brownish-black, with some males exhibiting yellowish colors, and females orange color, on the lateral sides of the body. The young are bright green and unmarked except for black tail bands, present also on adults.

Habitat: The Western Spiny-tailed Iguana lives mainly in seasonally-dry deciduous tropical forest, but can also be found in thorn forests and rarely associated with human settlements (Suazo and Alvarado 1994). They are generally not found existing in suburban and small agricultural areas as with the Sonoran Spiny-tailed Iguana (Ctenosaura macrolopha) because of the strong hunting pressure on this species. They are also not found in coastal swamps, volcanic or karstic areas, or high elevation plateaus and mountains which are habitats within their extent of occurrence. This iguana predominantly lives in humid climates with dry winters, an average annual temperature of 16–30°C, and average annual rainfall of 30–200 cm. The dry season may extend from 6–10 months per year. The probable distribution area includes climate classifications of: 1) semi-arid, arid, and very arid, 2) sub-humid temperate, and 3) semi-cold with cool wet summers.

This iguana inhabits hollowed trees, cacti, rocky areas, or they build burrows in sandy soil mostly near rivers. In areas where they are not hunted, they may live in cavities in rural buildings and rock piles. Feeding habits change for this species according to age: hatchlings eat mostly insects, leaves become more important than insects for juveniles, and adults primarily feed on many species of flowers, leaves, and fruit. Favored foraging trees are Spondias purpurea and Coquito (Pseudobombax ellipticum). They tend to forage very close to their retreats.

Range: In Mexico it is found from central Sinaloa to southern Chiapas. It has also been introduced to the United States in the very southern tip of the state of Texas and in the state of Florida.

Found in these States: FL | TX

Diet: Juveniles consume a diet consisting mostly of insects. However, adults are primarily herbivorous, eating a variety of flowers, leaves, stems, and fruit, but they will opportunistically eat small animals, eggs, and arthropods.

Reproduction: Mating of C. pectinata occurs in the spring. Males show dominance and interest by head bobbing, eventually chasing the female until he can catch her and subdue her. Within eight to ten weeks, the female will dig a nest and lay clutches of up to 50 eggs in a burrow of loose soil. These eggs hatch in 90 days with the bright green babies digging their way out of the sand.[15] The bright green hatchlings first appear around July and are abundant in August.

Status: The Western Spiny-tailed Iguana is widely, but unevenly distributed throughout western México to the southern part of the Tehuantepec Isthmus in Oaxaca. In this area, 36% of their habitat has been converted to large- and small-scale agricultural, ranching, and urban uses. It is suspected that there has been a decline in the iguana population correlated with this habitat loss; the majority of this habitat loss occurred more than three generations ago. The population seems to be structured in isolated subpopulations, with very large concentrations in some areas and absent in others. There are no data available on the population trends or fine-scale density and size information. They are hunted extensively for human food, medicinal uses, and handicrafts, from wild and cultivated sources. Density has been observed to be over 100 times greater in areas where they are not hunted. The level of consumption is not fully known but estimated to be in the tens of thousands annually.

Taxonomy: