Green Iguana

(Iguana iguana)




Facts about this animal

This large arboreal lizard grows to 1.5 meters in length from head to tail, although a few specimens have grown more than 2 meters. Mature iguanas weigh between 4 and 6 kg, but some with proper diet can reach up to 8 kg. Although predominantly green, these animals are actually variable in color. Thus the color of an individual may vary based upon its sex, mood, temperature, health, or social status. Additionally, such color alteration may aide these animals in thermoregulation. In the morning, while body temperature is low, skin color will be darker, helping the lizard to absorb heat from sunlight. However, in the hot mid-day these animals become lighter or paler, helping to reflect the sun rays and minimizing the heat absorbed. Active dominant iguanas usually have a darker color than lower-ranked iguanas living in the same environment. Most color variation seen in this species is exhibited by males, and may be attributed in part to sex steroids. Six to eight weeks prior to and during courtship, males may acquire a bright orange or gold hue, although coloration is still related to dominance status. The tail in addition to its green color, has black stripes. Mature females, for the most part, retain their green coloring. Other distinguishing features of this species include a pendulous dewlap under the throat, a dorsal crest made up of dermal spines that run from the mid neck to the tail base, and a long tapering tail. The dewlap is more developed in adult males than females. Extensions of the hyoid bones stiffen and support the leading edge of this structure, which is used in territorial defense or when the animal is frightened. This fleshy structure also serves in heat absorption and dissipation when it is extended. The laterally situated eyes are protected mainly by a immovable upper eyelid and freely mobile lower eyelid. Green iguanas have long fingers and claws to help them climb and grasp. Most green iguanas reach sexual maturity between three and four years of age. They tend to breed in the dry season, ensuring that young hatch in the wet season when food is more readily available. Mating appears to be polygynandrous (females pair with several males, each of which also pairs with several different females). Courtship occurs within a defined territory where more than one female may be present. Conflicts between males are not uncommon. Courtship behavior of males includes head bobbing, extending and retraction of the dewlap, color changes and nuzzling or biting a female’s neck Dominant males may also mark rocks, branches, and females with a waxy pheromone-containing substance secreted from their femoral pores. During mating, the male approaches the female and climbs on her back, straddling her. To restrain his mate, he grips her shoulder skin with his teeth, sometimes causing wounds. The male then pairs his cloacal vent up with the female's and inserts one of his hemipenes into her cloaca. Copulation can last for several minutes. Female iguanas can save sperm for several years, allowing them to fertilize eggs at a much later date. Females lay their eggs about 65 days after mating. Over a three day period, averages of 10 to 30 eggs are deposited into a nest. Nests are located 45 cm to more than a meter deep, and may be shared with other females if nesting areas are limited. Females may also display some of these behaviors when nesting sites are limited. Females may migrate to the same nesting site for several years in a row, then travel back to their home territory once their eggs are laid In fact green iguanas may travel occasionally considerable distances. Incubation lasts from 90 to 120 days (with a temperature from 29.5 to 33 degrees Celsius). Upon hatching, the length of green iguanas ranges from 17 to 25 cm. and they weigh app. 12 gr. Young are independent from birth. Adult green iguanas are primarily herbivorous. Green leafy plants or ripe fruits are their preferred foods. However they occasionally eat a small amount of carrion or invertebrates.

Did you know?
The iguana has been used as a food source in Central and South America for the past 7000 years. In fact they are often referred to as gallina de palo, "Bamboo Chicken" or "chicken of the tree". It is believed that also the populations in the Caribbean were translocated there from the mainland by various tribes as a food source. The coloring of the skin helps camouflage the green iguana, which means that they blend in easily to their surroundings to remain undetected by predators. If they are detected however, and need to escape quickly, they can dive from trees into water, and swim well. Green iguanas are quite sturdy- they can fall 12-15 m to the ground without getting hurt (they use their hind leg claws to "hook" leaves, branches, or anything in a "clasping" motion to break the fall) Their whiplike tails can be used to deliver painful strikes and like many other lizards, if caught by a predator by the tail, the iguana can allow it to break, so it can escape and eventually regrow a new one. By the way, green iguana skin is very tough to avoid cuts and scratches. Green iguanas have evolved a photosensory organ on the top of their heads called the parietal eye or “third eye”, “pineal eye” or “pineal gland”. This “eye” doesn’t work the same way as a normal eye does as it has only a rudimentary retina and lens and thus cannot form images. This sense organ serves however as a meter for solar energy, and aids in the maturation of sex organs, thyroid gland, and endocrine glands The visual effect of this "eye" is mostly limited to the detection of changes in light and dark and can thus detect movement. This therefore helps the iguana when being stalked by predators from above.


Name (Scientific) Iguana iguana
Name (English) Green Iguana
Name (French) Iguane vert
Name (German) Grüner Leguan
Name (Spanish) Iguana verde
CITES Status Appendix II
CMS Status Not listed



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Range Anguilla (introduced) , Aruba , Belize , Bolivia , Brazil , British Virgin Islands , Cayman Islands, Colombia , Costa Rica , Ecuador , El Salvador , French Guiana , Grenada , Guadeloupe , Guatemala , Guyana , Honduras , Mexico , Montserrat , Netherlands Antilles , Nicaragua , Panama , Paraguay , Peru , Puerto Rico , Saint Lucia , Saint Vincent and the Grenadines , Suriname , Trinidad and Tobago , United States , United States Virgin Islands , Venezuela
Habitat Tropical rainforest areas, generally in lower altitudes in areas near water sources, such as rivers or streams. Green iguanas live high in the tree canopy. Although preferring a forested environment, they can however adjust well to a more open area.
Wild population Like many other tropical species, the green iguana is potentially threatened by habitat destruction.
Zoo population 842 reported to ISIS (2008)

In the Zoo

Green Iguana


How this animal should be transported

For air transport, Container Note 41 of the IATA Live Animals Regulations should be followed.


Find this animal on ZooLex


Photo Copyright by
Cary Bass

Why do zoos keep this animal

The green iguana is not a currently threatened species. zoos keep it primarily for educational reasons as a large and conspicuous representative of the lizards, and as an ambassador species for the conservation of neotropical forests.

Green iguanas are popular pets, and zoos may often come into postion to accept abandoned or not properly kept specimens for animal welfare reasons.