The green iguana is one of the iconic species of the neotropical rainforest. This species has an extensive range stretching from Northern Central America southward throughout the Amazon Basin. They’ve also been introduced in South Florida, as well as the lower Rio Grande area of South Texas. Green iguanas are the largest lizard in the Amazon Basin, including the Peruvian Amazon, and large males may reach six feet in length. Females are considerably smaller, reaching about four feet in length.
Unfortunately, the green iguana has been collected over a wide range for the U.S. and European pet trade. Most baby iguanas do not survive due to very poor husbandry. The few that do survive, once reaching four, five or even six feet in length typically are not good pets as they require huge cages and tend not to be friendly. Bites from a large iguana may result in serious injury. I have a very large male that is an incredible gentle giant. This animal is used in reptile programs, and is often the star of the presentation.
Along the river bank of the Amazon and its tributaries, watch carefully in the trees and especially in the large vine mats hanging down to the water’s edge. These are favorite “hangouts” for iguanas which IE’s local naturalists are familiar with, so hopefully every Amazon cruise  guest will be fortunate enough to find a big male iguana basking in the tropical sun.
What a Male!
What are most striking about iguanas are the males of the species. A huge male is an amazing creature with a very large dewlap that hangs very low from the throat. They also exhibit a long row of spines down the back from the neck to the base of the tail. The tail is long and in many individuals, banded in colors of greenish olive and brown. The body of a male iguana may be olive early in the morning before they have had time to warm up, but once warming occurs, they may become bright orange with large bluish cheeks.
Green iguanas are basically herbivorous, but will also eat bird’s eggs, baby birds and young rodents when they can find them. Interestingly, in captivity, it is important not to provide too much protein in the diet of an iguana as they are very prone to health problems as a result too much protein in their diet.
Another very interesting characteristic of the iguana is the presence of a parietal eye or “third eye” — a whitish diamond shape feature in the top of the head. The parietal eye is photo-sensitive and tells this lizard when to wake up, and can detect shadows, possibly warning the lizard of a predator above them, such as a hawk or eagle.
Naturalist Greg Greer  is a favorite among IE travelers, and has gained a reputation for his friendliness and good humor, along with his incomparable knowledge of natural history, photos and articles have been widely published in books and magazines, including Georgia Outdoor News, Bird Watcher’s Digest, Alabama Outdoor News, Riversedge and Southern Wildlife.