The blue iguana is a large, long-tailed scaly reptile exclusive to Grand Cayman Island, southwest of Cuba. A rare iguana species, its natural habitat is generally tropical dry forests and sandy shorelines. Once plentiful, this species of iguana is now considered extremely endangered. In 2002, there were only about 15 known adults in the region. Conservationists have set up captive breeding programs to give blue iguanas an opportunity to reach self-sustainable levels, but the human and pet intrusion into the Grand Caymans is making this a difficult task.
The blue iguana is not a social animal—females and males usually live apart, except in breeding season. After breeding in the spring months, they again go their separate ways. The female blue iguana typically digs a hole in soft soil and deposits from one to two dozen eggs. After these eggs have incubated for two to three months, it typically takes several days for the baby iguanas to emerge, though these juveniles are fully-formed and able to fend for themselves. Adult blue iguanas are believed to live multiple decades.
The male blue iguana is typically larger than the female, growing up to five feet (1.5 meters) in length and weighing up to 30 pounds (13.6 kilograms). When resting, both sexes are a blue-gray color, but during breeding season or territory-guarding, the female takes on a powder-blue appearance, while the male becomes a bright, vibrant blue. Juvenile blue iguanas are usually a muted brown with pronounced dark markings that disappear as they mature.
Blue iguanas are primarily herbivores, reportedly feeding on almost 50 different plant varieties. This iguana usually eats fruit, flowers, and leaves, but has been known to eat slugs, insects, and carrion. Primarily terrestrial, the blue iguana sometimes ventures into trees. Its flower and fruit diet generally increases plant diversity and strength. Seeds that pass through a blue iguana’s digestive system typically sprout earlier and are hardier than those that do not.
The blue iguana is highly susceptible to predators. The native snake population feeds on the eggs, and increasing numbers of domestic and escaped dogs and cats prey on the juveniles and adults. As dangerous as these predators are, habitat loss is the blue iguana’s largest threat. Housing developments, commercial building, farming, and livestock grazing typically make it extremely difficult for the blue iguana to find food and safe breeding grounds.
Captive breeding programs typically sponsored by zoos and conservation organizations are slowly beginning to increase the number of blue iguanas on Grand Cayman. There are two breeding populations on the island and some 25 zoos in the United States aiding in the recovery effort. From a non-viable wild population of only five to 15 blue iguanas, conservation efforts have reintroduced over 200 individuals into their native habitat, mainly into Queen Elizabeth II Botanic Park and the Salina Reserve.