Distribution and habitat
Ranging throughout Hispaniola, Haiti and the Dominican Republic; Rhinoceros Iguana populations are stable only on Isla Beata and the extreme of the Barahona Peninsula inside Parque Nacional Jaragua. There are moderately dense populations in the southeastern region of Haiti and its offshore islands including the saltwater lake of Etang Saumatre. Populations in Haiti are even more endangered due to the deforestation and human clearing practices. In general, the iguanas are found most abundantly in, although not restricted to, scrub woodland, dry forests characterized by xeric, rocky habitats of eroded limestone in coastal terraces and lowlands of the mainland and several offshore islands and small cays in a variety of subtropical life zones and habitat types.
An individual was photographed on May 4, 2008 on the Limbe Island in Northern Haiti. It had been caught by a group of fishermen from Bas-Limbe, Bord de Mer village. The Rhinoceros Iguanas caught on Limbe Island are eaten by the local population. This siting represents a new area previously not thought to be in the Cyclura cornata's range.
The Rhinoceros Iguana is a diurnal species living primarily in rocky outcroppings with little vegetation for cover. Although quick to flee when attacked or threatened, they will aggressively attack by biting and repeatedly striking with their thick tail if cornered.
Diet
The Rhinoceros Iguana, like most Cyclura species is primarily herbivorous, consuming leaves, flowers, berries, and fruits from different plant species. A study in 2000 by Dr Allison Alberts of the San Diego Zoo revealed that seeds passing through the digestive tracts of Cycluras germinate more rapidly than those that do not. These seeds in the fruits consumed by cycluras have an adaptive advantage by sprouting before the end of very short rainy seasons. The Rhinoceros Iguana is also an important means of distributing these seeds to new areas (particularly when females migrate to nesting sites) and, as the largest native herbivores of their island's ecosystem, they are essential for maintaining the balance between climate and vegetation. Rhinoceros Iguanas do appear to be opportunistic carnivores as individual animals have been observed eating small lizards, snakes, and insects.
Mating
Male Rhinoceros Iguanas, unlike other members of the genus Cyclura, reach sexual maturity at four to five years of age. Females become sexually mature at two to three years of age. Male Rhinoceros Iguanas are territorial and the most aggressive males will have the largest range of territory. Mating takes place at the beginning of, or just prior to, the first rainy season of the year (May to June) and lasts for two to three weeks. Females lay from 2 to 34 eggs, with an average clutch size of 17, within 40 days. Females guard their nests for several days after laying their eggs, and incubation lasts approximately 85 days. It has been noted that their eggs are among the largest lizard eggs produced in the world.
Endangered status
Although Rhinoceros Iguanas are the most common species of Cyclura kept in captivity there remain approximately 10-16,000 of these animals in the wild. A successful breeding program existed at the Parque Zoológico Nacional of the Dominican Republic (ZooDom) from 1974 to 1994, with an average of 100 babies hatching annually. These efforts included reintroductions of captive-bred "head-started" young to several protected areas in the southwest Dominican Republic in order to reduce the odds of predation by snakes and feral animals such as mongoose or cats. The program has not continued since 1995, due to an administrative change at the zoo.
As of 2009, a reintroduction of rhinoceros iguanas on the Samana peninsula is planned by the Iguanario de los Tocones.
Captivity
The Rhinoceros Iguana is well established in captivity, both in public and private collections. Rhinoceros Iguanas in captivity throughout the United States totals 39 males, 32 females, and 36 undetermined individuals at 20 zoological institutions, with an additional 533 animals of unassigned subspecies, reported by seven American Zoological and Aquarium Association institutions. The actual number may be much higher considering animals kept at European and Asian zoos and the many kept as pets in private collections. As a result, the demand for wild-caught animals to supply zoos and the pet trade has been reduced.
Despite these numbers, making them also the most numerous species of Cyclura, they are still considered a CITES (Convention on International Trade in Endangered Species) protected animal.
