West Indian Iguana

Male Lesser Antillean iguanas form a dominance hierarchy, with the most dominant individual easily discernible by his dark grey colouration. This powerful status, which allows the easiest access to females, is achieved through displays that involve side-walking followed by head-to-head pushing contests with arched tails. Fighting between males is rare, but can be fierce. Each dominant male actively defends a small territory containing between one and seven females during the reproductive period, deterring other males from interfering by bobbing the head up and down. Reproduction is synchronised to the fresh plant growth of the wet season to ensure hatchlings begin life with plenty of food. Females may migrate to warm and sandy nest sites up to 900 metres from their home range, where they will lay between 8 and 18 eggs in a one metre long, excavated tunnel, ending in a chamber large enough for the female to turn around. The eggs are incubated by the heat of the sun for three months, after which time the hatchlings emerge and disperse into the surrounding vegetation. Young iguanas live mainly on the ground, in areas with thick vegetation offering protection, basking sites and food. With age, the Lesser Antillean iguana spends time higher up in the trees. Sexual maturity is reached at around three years, but males will not breed until they can achieve dominance. Lesser Antillean iguanas live for up to 15 years (2). Feeding mainly in the morning, this iguana consumes leaves, flowers and fruits, and may eat plants toxic to other species. They will feed on proportionally more fruit in the wet season as it becomes more abundant, but will also eat meat when possible. The eggs of the Lesser Antillean iguana are eaten by snakes, birds, opossums and lizards, but adults are free from the risk of predation, except by humans (2).

The Lesser Antillean iguana is legally protected from hunting throughout its range, but law enforcement is limited. It occurs only in one protected area: Cabrits National Park on Dominica. Proposals for the creation of nature reserves in other areas of the iguana's range have been put forward, and research into the population biology, ecology and conservation management plans is underway. Captive breeding programmes are run at Durrell Wildlife Conservation Trust, Memphis Zoo and San Diego Zoo (2).

Male Lesser Antillean iguanas boast enlarged scales running the length of the back and enlarged spikes on the dewlap. Dominant males turn from green to dark grey, and when reproductively active will flush pink in the jowls and become pale-blue in the scales on the sides of the head. Females are more strikingly coloured, with a uniformly bright green body, pale head and brown tail. Hatchlings and juveniles are also bright green, but have white flashes from the jaw to the shoulder and three vertical white bars on the sides of the body. They also have brown flashes which darken when the individual is stressed. With age, the white flashes and the ability to change colour are lost, and the tail turns brown, beginning at the tip and working up to the base (2).

Inhabits scrub and scrub woodland, mangrove and low altitude rainforest of various qualities (2).

Once present throughout the Lesser Antilles of the Caribbean, the Lesser Antillean iguana is now confined to the islands of the northern Lesser Antilles, including Anguilla, St. Martin, St. Eustatius, St. Barthélemy, Antigua, Guadeloupe, Dominica and Martinique (2).

The Lesser Antillean iguana is classified as Vulnerable (VU A1acde + 2cde, B1 + 2abcde) on the IUCN Red List 2004 (1) and is listed on Appendix II of CITES (3).

In the past, the Lesser Antillean iguana has been brought to near or total local extinction by clearance of suitable habitat for agriculture on St. Kitts, Nevis, Basse Terre and St. Eustatius. Now, tourism has taken over from agriculture as their chief industry and coastal development has further decimated iguana habitats, particularly affecting communal nest sites (2). Feral predators continue to reduce Lesser Antillean iguana populations. On all islands on which the Indian mongoose occurs, this iguana is extinct or highly endangered. Cats and dogs all contribute to the decline, as do goats and sheep which over-browse, causing a change in plant species composition and habitat structure (2). Hunting of the Lesser Antillean iguana was prevalent for several decades, and although it is now illegal, it continues and is common in some areas. Accidental road kills are also a problem, principally because the majority of deaths are of migrating pregnant females and dispersing hatchlings (2). A further threat is the confirmed hybridisation between Lesser Antillean iguanas and common iguanas (Iguana iguana). With no obvious environmental changes in Les Iles des Saintes, the disappearance of the Lesser Antillean iguana has been attributed entirely to displacement and hybridisation with the common iguana (2).