These iguanas belong to the genus Cyclura , a group of lizards found only in the West Indies. Obtaining a length of 59 inches and weighing 7 kg, the Cayman Island rock iguana is among the largest of the genus. A distinctive characteristic for the iguana is a blood red sclera. Also, unlike some other Cyclura , the Cayman iguana displays sexual dimorphism.
Females are gray or brown with faint, dark lateral bands.
Males are marked with alternating black and yellow-brown bands, have a wider head, and a more pronounced dewlap. The iguanas' present day habitat is restricted to the inner areas of the islands. They make use of the natural crevices in the xeric limestone for shelter. They are opportunistic omnivores, usually feeding on vegetables, flowers, insects, some rodents and carrion. In 1990 the Shedd Aquarium obtained 10 juvenile C. n. caymanensis on breeding loan from an institution in Florida.