Rhinoceros iguana

Appearance

The rhinoceros iguana, like other members of the genus "Cyclura", is a large-bodied, heavy-headed lizard with strong legs and a vertically flattened tail. A crest of pointed horned scales extends from the nape of their neck to the tip of their tail. Their color is a uniform gray to brown drab. Most adults weigh 4.56 kilograms to 9 kilograms

These iguanas are characterized by the growth of bony prominent tubercles on their snouts which resemble horns. Dr. Thomas Wiewandt, who spent an extended period on Mona Island studying "Cyclura cornuta stejnegeri", suggested that the horns, along with lateral spines and prominent parietal bulges, function as protective armor against sharp rocks or as defensive tools to facilitate the escape of males from the grasp of one another. Males possess an adipose pad in the form of a helmet on the occipital region of the head, and a large dewlap. This species, like other species of "Cyclura", is sexually dimorphic; males are larger than females, and have more prominent dorsal crests and "horns" in addition to large femoral pores on their thighs, which are used to release pheromones.

Naming

Their name derives from the bony-plated pseudo-horn or outgrowth which resembles the horn of a rhinoceros on the iguana's snout.

Distribution

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 sighting represents a new area previously not thought to be in the range of "Cyclura cornata".

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.

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 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.

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 sighting represents a new area previously not thought to be in the range of "Cyclura cornata".

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.

Food

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 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.