Green iguana  (Iguana iguana)

Biology

Primarily a tree-dwelling reptile (3), the green iguana is a specialised leaf-eater, consuming the tender green leaves and flowers of a selection of trees, shrubs and herb vegetation (4). For over 90 percent of the time, green iguanas are inactive and often when they do move, they travel slowly. However, if required, green iguanas are capable of running fast and will dive into water to escape predators (4), revealing their excellent swimming abilities. This explains the iguana's preference for habitat close to watercourses (3).

Green iguanas are territorial during the breeding season (4), and will defend their home range against intruders (3). If a green iguana ventures into the territory of another it will be met firstly with pronounced head-nodding behaviour, believed to be an intimidating action. This may be followed by an extensive threat ritual, when the iguanas vertically flatten their bodies and erect their dorsal crests to create the appearance of being much larger. If the altercation does not end there, serious fights with injuries can follow. The dewlap, which can be lowered by a bone in the neck, is also used in threat displays, as well as for communicating with other green iguanas (3).

Green iguanas breed during the dry season, during which time a territorial male occupies his territory with several females (4). A month or two after mating, the females move to communal nesting sites where they lay a clutch of 17 to 76 eggs in burrows dug into the ground. Iguana hatchlings emerge from the nest after three months of incubation, coinciding with the onset of the rainy season, a strategy to ensure plentiful, lush, green vegetation for the growing iguanas to feed on (4). Green iguana hatchlings are incredibly vulnerable to predators, including other reptiles, birds and mammals (7), and only about 2.6 percent live to the age of one year. Sexual maturity is reached after two to three years (4).