Human Journey

Grand Cayman Tries to Eradicate Invasive Green Iguanas

Perched on a fence, glaring down from a shady palm tree or wriggling quickly across the road are the Cayman island’s most populous visitors: the green iguanas. These dinosaur-like lizards, native to Central and South America, have made Grand Cayman their home since the 1980’s, when they multiplied in the wild after they were brought over as pets. The scaly green reptiles are excellent swimmers, and can often be found hanging off of both trees and buildings near the water. These majestic looking creatures may intimidate some of this Caribbean island’s tourists, but these herbivores are peaceful and non-aggressive animals, providing an exciting presence for wildlife enthusiasts.

But while the green iguanas were initially protected under the law, this invasive species has long outstayed its welcome. Before 2010, Cayman law made it illegal to kill iguanas, in a desperate attempt to save the critically endangered native blue iguana. But for the past two years, the Department of Environment has been trying to reduce the green iguana population by killing the giant lizards.

The DoE fears the iguanas could massively invade Little Cayman and Cayman Brac, where so far only a few of the greens have been spotted. While the DoE no longer responds to calls regarding the unmanageable population of iguanas on Grand Cayman, it is trying to prevent them from inhabiting the Sister Islands.

“They have to cull them,” said Bonnie Edwards, a liaison on an upcoming iguana survey, “We love all iguanas, but the green ones don’t belong here and they are a threat to the native rock iguana.”

But regardless of their uncontrollable population, the green iguanas remain a fascinating species. Scientists are studying their social behavior to better understand how herbivorous dinosaurs behaved 65 million years ago.

The dinosaur genus Iguanodon, meaning “iguana tooth,” was named because its beak-like mouth and back teeth resembled those of an iguana. Green iguana babies, like many herbivorous dinosaurs, form social bonds and travel in groups for survival.

And while the Cayman’s native blue iguanas more often appear on postcards and travel brochures, the green ones continue to pose majestically for tourists’ photographs as the five foot long lizards munch peacefully on leaves, flowers and fruit. With no natural predators on the island, it looks like the green iguanas are there to stay.

Nicole Glass is a Washington, D.C.-based freelance journalist and a contributing writer at National Geographic News Watch. She also writes for USA TODAY, The Huffington Post, Russia Today (RT TV) and Demand Media. Previously, she was Assistant Editor and later Weekend Editor of, David Frum's political news outlet (now a part of The Daily Beast). She grew up abroad, has moved more than 15 times and has visited more than 40 countries. Visit her website, to see her published works and follow her on Twitter @NicoleSGlass.
  • Su-Jin

    Hi there,
    I read the article and was just wondering. How does the presence or over-population of the green iguana a threat to the blue iguanas? Is it because they have to compete for the same diet of plant parts (e.g. flowers, leaves)? But from my understanding, both live in very different habitats – the green iguana, mostly on trees, while the blue iguana mostly along the coast on rocky shores. Could competition for food still occur then?

  • MosKito

    Terrible story as it is the human always invading everything and hereafter decides what can stay and what is to kill.

    I like green iguanas and have had two by myself, since last week my little lady died. My big fella is 7 years old and living most of the day outside in the garden…. I will never understand how an animal which only eats leaf and some fruits will endanger a country

    If you are in Asia, Thailand, Malaysia or elsewhere, pls feel free to contact me regarding questions of our green friends or if you have a new girlfriend for my big boy

    24moskito AT

  • Trinity jones

    I read this article on these lizard they are wondreful i am so suprised by this and that it took us this long to find these lizards.


    Good article

  • […] The green iguana is a peaceful herbivore, but it is still dangerous to the island. The large lizard poses a threat to Grand Cayman’s natural resources. They strip the bark from trees in the wild, damage gardens and farms, and compete with indigenous species for food sources. Grand Cayman has already been overrun with green iguanas, and the government fears that they will spread to Little Cayman and Cayman Brac.[1] […]

  • […] Photo credit: National Geographic […]

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