White Cay Ground Iguana

Measuring 300 to 390 mm (12 to 15 in) in snout-to-vent length (SVL) when full grown, the San Salvador rock iguana is a colorful lizard, the coloration varying between subspecies as well as between individual specimens. The lizard's back color can range from red, orange or yellow, to green, brown or grey, usually patterned by darker markings. The very brightest colors (red, orange, blue, or yellow) are normally only displayed by males and are more pronounced when at warmer body temperatures. Immature iguanas lack these bright colors, being either solid brown or grey with faint slightly darker stripes. This species, like other species of Cyclura, is sexually dimorphic; males are larger than females, and have more prominent dorsal crests as well as larger femoral pores on their thighs, which are used to release pheromones.

Once inhabiting all the large islands of the Bahamas, today C. rileyi is confined to six populations in small remote cays of three island groups: San Salvador Island, Acklins, and Exuma. A study in 1995 estimated there were between 426 and 639 specimens left in the wild, and that this number has likely been reduced since much of their habitat was destroyed in 1999 by Hurricane Floyd. The three island groups, each harboring its own subspecies, are on separate banks and were not connected during the last glacial period when water levels were 100 m (330 ft) lower than they are at present.

Like all Cyclura species, the San Salvador rock iguana's diet is primarily herbivorous, 95% of which comes from consuming leaves, flowers and fruits from 7 different plant species such as seaside rock shrub (Rachicallis americana), and erect prickly pear (Opuntia stricta). This diet is very rarely supplemented with insect larvae, crabs, slugs, dead birds and fungi.

The San Salvador rock iguana is an endangered species of lizard of the genus Cyclura in the family Iguanidae. First described by Leonhard Stejneger in 1903, it is known commonly in the Bahamas as simply "iguana". Its specific name, rileyi, is a Latinized form of the surname of American ornithologist Joseph Harvey Riley, who collected the holotype.

Subspecies. As of 1975 two additional subspecific forms have been identified along with the nominal subspecies: the Acklins ground iguana (C. r. nuchalis) and the White Cay iguana (C. r. cristata). Together they are one of the most threatened species of all the West Indian rock iguanas and are described as critically endangered according to the current IUCN Red List.