Iguana
The green iguana is a large arboreal lizard native to Central and South America and the Caribbean. Recognized by its vivid green scales, a spiny crest running along the back and a long lashing tail, it usually measures 1.2 to 1.7 meters from snout to tail tip, and large males reach about 2 meters. Primarily herbivorous, it feeds on leaves, flowers and fruit and plays an important role in seed dispersal across tropical forests. It spends long hours basking to regulate body temperature and is an agile climber and swimmer. Although widely distributed and listed as Least Concern, it faces hunting pressure for meat, capture for the pet trade, and has established invasive populations in Florida, Puerto Rico, Taiwan, Hawaii and other regions.
Iguana species: green, marine, blue and more
When people say iguana they usually mean the green iguana, Iguana iguana, also called the common or American iguana, which is the species on this page and the one found across the Americas and in many introduced populations. The genus Iguana has only a few species: the green iguana, the critically endangered Lesser Antillean iguana, and two Caribbean island forms described as separate species in 2020. Many other lizards in the iguana family carry the name too, around 45 species in all. The marine iguana, or sea iguana, lives only in the Galápagos and is the only lizard that feeds in the sea, diving for algae. The blue iguana is a large rock iguana from Grand Cayman, brought back from the edge of extinction by a breeding program. The black iguana is a spiny tailed iguana of Mexico and Central America, faster and more meat eating than the green iguana. Desert iguanas, land iguanas, rhinoceros iguanas and the Fiji iguanas, which have their own page on this site, complete the family.
Where do green iguanas live?
The green iguana is native to the tropical lowlands of the Americas, from Mexico through Central America to South America as far south as Paraguay, Bolivia and eastern Brazil, and to many islands of the southern Caribbean such as Trinidad and Tobago. It lives below about 1,000 meters in rainforest, dry forest, mangroves, riverbanks and coastal scrub, and it is almost always near water: it rests on branches that hang over rivers and drops into the water to escape. It also adapts well to people and is common in parks, gardens, hotel grounds and canals, such as the Parque Seminario in Guayaquil, full of tame iguanas. Outside its native range it has been introduced, mostly through the pet trade, to Florida, Hawaii, Puerto Rico, the Dominican Republic, the Bahamas and other Caribbean islands, Fiji, Japan's Ishigaki Island and Taiwan, where it has become invasive. It needs warm weather all year and cannot survive long cold spells, which limits how far north it can spread.
What a green iguana looks like and how big it gets
Green iguanas are big lizards: adults usually measure 1.2 to 1.7 meters including the tail, and the largest males reach about 2 meters. Most adults weigh 4 to 6 kilograms, and big males can reach about 8. More than half of the length is the tail, long, muscular and banded, used for balance, swimming and whipping attackers. A crest of soft spines runs from the neck down the back, longest in adult males, and a large dewlap hangs under the throat, used for display and to help gain or lose heat. Below each ear sits a large round scale, the subtympanic shield, a good way to identify the species. On top of the head is a small pale scale that covers the parietal eye, a light sensitive organ that detects shadows from above. Despite the name, not all green iguanas are green: young ones are bright green, but adults can be gray, brown, bluish, reddish or orange depending on the region and the season, and some populations are almost black.
Why do iguanas change color?
Green iguanas cannot change color quickly or to match their background the way chameleons do, but their color does change over hours, seasons and years. The most common reason is temperature: a cold iguana turns darker, which helps it absorb heat from the sun, and becomes paler once it has warmed up. The biggest change happens in the breeding season, when adult males turn bright orange or orange red on the head, legs and dewlap to impress females and warn rival males; dominant males are usually the most orange. Iguanas also darken when they are stressed, sick or frightened, and their color changes with age, from the bright green of hatchlings, which helps them hide among leaves, to the duller grays, browns and oranges of older adults. Region matters too: iguanas from some Central American and Caribbean populations are naturally bluish, reddish or almost black.
What do iguanas eat?
Green iguanas are herbivores. They eat leaves above all, along with flowers, fruit and young shoots from many kinds of trees, vines and shrubs, and they spend much of the day in the canopy feeding. Their gut has a large chamber where bacteria ferment the tough plant fibers, a little like a cow's, and hatchlings get those bacteria by eating the feces of adults. Digestion only works well when the iguana is warm, which is why they bask before and after eating. Young iguanas sometimes eat insects, and adults may take an occasional egg or bit of carrion, but meat is not a normal part of their diet. In gardens and farms they eat flowers, fruit, vegetables and ornamental plants such as hibiscus and orchids, which is one reason they are unpopular in Florida and Puerto Rico. By eating fruit and passing the seeds, they help spread plants along forest edges and riverbanks.
Behavior: basking, falling and swimming
Green iguanas are active by day and spend many hours basking high in trees, usually on branches over water. Adults are territorial, and males defend the best perches with head bobbing, extending the dewlap and standing tall, and fight if needed. When threatened, an iguana first freezes and trusts its camouflage, then flees: it can drop from branches 12 to 15 meters high into water or onto the ground without being hurt, and it is an excellent swimmer, folding its legs against the body and sweeping its tail from side to side. It can stay underwater for a long time when hiding. If cornered, it stands sideways to look bigger, hisses, bites and lashes with its tail, and like many lizards it can drop part of the tail, which later grows back. Iguanas also use body language to communicate, and head bobbing is a sign of territory, courtship or warning.
Reproduction: nests and baby iguanas
Green iguanas breed once a year, at the start of the dry season in much of their range. Males turn orange and court females with head bobs, and a dominant male may mate with several females in his territory. About two months later the female digs a burrow, often one to two meters long, in sandy or loose soil in a sunny spot, and lays a clutch of usually 20 to 70 eggs. In places with few good nesting sites, many females dig in the same area, sometimes sharing burrows. The eggs incubate in the warm soil for about 10 to 15 weeks, and the hatchlings emerge at the start of the rainy season, when new leaves are plentiful. Young iguanas often stay together in small groups for their first year, which may help them spot predators. Snakes, birds of prey, herons, cats, dogs and large lizards eat many of them, and the survivors reach maturity at around two to three years.
Invasive iguanas: Florida, Puerto Rico and Taiwan
The green iguana is one of the best known invasive reptiles in the world. Escaped and released pets founded populations in South Florida from the 1960s, and today iguanas are common from the Keys to Palm Beach and beyond, digging burrows that damage seawalls, canal banks and sidewalks, eating gardens and leaving droppings around pools and docks. Florida now bans keeping them as pets without a permit and encourages owners to remove them from their property. During cold snaps in South Florida, iguanas become so cold that they lose their grip and fall from trees, stunned but often still alive, a scene that makes the news almost every winter. In Puerto Rico, where they are called gallinas de palo, there are thought to be millions. Taiwan estimated around 200,000 in its south and center and removed more than 100,000 in 2024 alone. Smaller invasive populations live in Hawaii, the Dominican Republic, the Bahamas, Fiji and Japan's Ishigaki Island.
Is the green iguana endangered?
No. The IUCN lists the green iguana as Least Concern, since it is widespread, adaptable and common in many places. Even so, many native populations have declined. Iguanas have been hunted for food for thousands of years, and their meat and eggs are still eaten across Central and South America, where the iguana is known as gallina de palo or bamboo chicken, and in Nicaragua and El Salvador it is a traditional dish during Holy Week. Deforestation removes nesting and feeding areas, and the international pet trade has exported millions of young iguanas, mostly from farms in Central and South America. Iguana farming was promoted in Panama and Costa Rica from the 1980s as a way to produce meat and release young iguanas while protecting forests. The species is listed in CITES Appendix II. Its close relative, the Lesser Antillean iguana, is critically endangered, partly because green iguanas introduced to its islands compete and hybridize with it.
Where it is found
The Iguana can be found in places such as:
