The Green Iguana (Iguana iguana), also known as the American iguana or simply iguana, is a large, arboreal, mostly herbivorous species of lizard of the genus Iguana. The word iguana comes from the Spanish form of the Taino name of the species: iwana. In some Spanish-speaking countries, males are called gorrobo or ministro and juveniles are called iguanita or gorrobito.
The green iguana ranges over a large geographic area; it is native from southern Brazil and Paraguay as far north as Mexico and the Caribbean islands, and have been introduced from South America to Puerto Rico and are very common throughout the island and considered an invasive species; in the United States, feral populations also exist in South Florida (including the Florida Keys), Hawaii, the U.S. Virgin Islands and the Rio Grande Valley of Texas.
Naturally 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 the hobbyist.
Green iguanas are great tree-climbers and will often bask on a tree branch to warm up in the morning. They often will stay close to water so they can make a speedy getaway from predators. They'll even jump from the trees into the water to evade capture. Their main predators include ocelots, margays, jaguars, caimans, boas, hawks, harpy eagles, and even piranhas. If cornered, the green iguana will extend and display the dewlap under its neck, stiffen and puff up its body, hiss, and bob its head at the aggressor. They can also use their long, whip-like tail, and their sharp teeth as means of defense.
While mainly herbivorous, there is evidence of wild iguanas eating grasshoppers, tree snails, bird eggs, dead fish, and even mice.
Recently, atrophied venom glands have been found in some species of iguanas such as the green iguana. In the past, the symptoms caused by bites were thought to have been from the bacteria in the iguana’s mouth (though this is still under debate). Iguanas retain characteristics of the ancestral venom system - glands on both upper and lower jaws (as opposed to more advanced venomous reptiles that only have venom glands on either the upper or lower jaws) which deliver small amounts of weak harmless venom.