The green iguana or common iguana (Iguana iguana) is a large, arboreal, mostly herbivorous species of lizard of the genus Iguana native to Central, South America, and the Caribbean. Usually, this animal is simply called the iguana. The green iguana ranges over a large geographic area, from southern Brazil and Paraguay as far north as Mexico and the Caribbean Islands. They are very common throughout Puerto Rico, where they are collaquially known as "Gallina de palo" and considered as an invasive species introduced from South America; in the United States feral populations exist in South Florida (including the Florida Keys), Hawaii, and the Rio Grande Valley of Texas.
A herbivore, it has adapted significantly with regard to locomotion and osmoregulation as a result of its diet. It grows to 1.5 metres (4.9 ft) in length from head to tail, although a few specimens have grown more than 2 metres (6.6 ft) with bodyweights upward of 20 pounds (9.1 kg).
Commonly found in captivity as a pet due to its calm disposition and bright colors, it can be very demanding to care for properly. Space requirements and the need for special lighting and heat can prove challenging to an amateur hobbyist.
In the aftermath of two Caribbean hurricanes in 1995, a raft of uprooted trees with a group of fifteen Green Iguanas landed on the eastern side of Anguilla – an island where that species have never been recorded previously. Biologist Ellen Censky, of the Connecticut State Museum of Natural History, believes that the new iguanas had accidentally become caught on the trees and rafted two hundred miles across the ocean from Guadeloupe, where Green iguanas are an indigenous species. By examining the weather patterns and ocean currents, Censky has shown that the iguanas had spent three weeks at sea before arriving on the island. This colony began breeding on the new island within two years of its arrival.
In February 2012, the government of Puerto Rico proposed that the islands' iguanas, which were said to have a population of 4 million and considered to be a non-native nuisance, be eradicated and sold for meat.