Observations on population and habitat trends recorded since the 1970s estimate that 10,000 to less than 17,000 Rhinoceros iguanas remain in the wild. Iguana densities are low in the majority areas where they presently occur and appear to be declining. Local extirpations are known from both the Dominican Republic and Haiti, and only ten sub-populations of Rhinoceros iguanas are known from the Dominican Republic.
Important threats to this species are habitat destruction stemming from human activities such as charcoal production, agriculture, mining, and livestock grazing. Feral dogs, cats, mongooses, and pigs also threaten iguanas, as well as illegal hunting by humans.
These big, heavy-bodied iguanas were once the largest animals on the Caribbean islands where they live. Their only enemies were--likely--birds of prey, such as hawks. Today, they are food for humans and their pets.
Like all squamates, this Rhinoceros Iguana is covered in scales--small, hard, platelike thickenings of the skin. Scales protect bodies and help reduce water loss. Unlike fish scales, squamate scales are specialized folds of skin.
Members of C. cornuta have a variable diet both seasonally and ontogenetically. Rhinoceros iguanas are mainly herbivores, eating a wide variety of leaves, fruits, flowers, and seeds. They occasionally eat animal food, mainly insects, land crabs, or carrion (especially dead birds and fish).
These iguanas hatch from eggs and are independent after hatching. They mature at 5 to 9 years of age.
There are two subspecies recognised for Cyclura cornuta. The nominate race, cornuta occurs on the island of Hispaniola (Haiti and the Dominican Republic). The remaining subspecies, stejnegeri is confined to Mona Island; however, subspecies status for stejnegeri is contentious as it is morphologically identical to cornuta.
Cyclura iguanas are all similar, however, the Rhinoceros Iguana is the only member of the Cyclura genus to posses an actual horn, hence their common and Latin name; cornuta meaning “horn”. They can be distinguished from other iguanid lizards by their dull grey colour, characteristic stocky build and their isolation to the islands of the West Indies.
Rhino iguanas are much more terrestrial than the green iguanas which allows them to live in rockier and drier areas. They are rarely found in trees or even forested areas
Rhino iguanas get their name because of horn-like structures that are found on the heads of males. It is not known if these structures serve any purpose, but may aid in courtship.