Common Name: Green Iguana
Scientific Name: Iguana iguana
Family: Iguanidae

Iguana demonstrating its dominance by lifting up its chest and displaying its dewlap
Iguana demonstrating its dominance by lifting up its chest and displaying its dewlap

Range and Abundance:
Specific to tropical regions of the world around the equator. They range anywhere from southern Mexico to central Brazil. They are extremely abundant and are considered an invasive species.

Iguanas are a greenish brown color with black stripes around its tail. They are able to slightly change their color depending on mood, behavior, and interactions within its environment. Different locations around the world contain the same Iguana iguana species in different colorations such as orange or even bluish purple. Young juvenile iguanas are bright green in color which slowly dissipates as they get older.

Iguanas contain spikes along their spine and tails which are used for protection. They also have an extremely long tail and large claws which are used to climb trees and hold on to branches as well as be used in self defense. They have very strong jaws which contain very tiny razor blade teeth used for cutting up flowers for digestion. Lastly they have a very large dewlap which helps regulate body temperature and aids in the mating ritual for males.

Tropical rainforests are an iguana’s preferred location. They are found in hot climates where humidity high and rain is abundant. They tend to situate themselves near river beds where they can easily regulate their body temperatures.

Because iguanas situate themselves near the river, they are easily susceptible to prey. They climb tall trees overlooking the river and bathe in the sun. This makes them exposed to predators such as large hawks and birds of prey. If an iguana sees or hears the sound of a hawk they will either freeze and stay motionless or fall off of the branch they are posted on and fall into the water. Because Iguanas are mostly herbivores, they have no competitors and find themselves only competing with each other for territories and/or mates.

Iguanas are independent reptiles that rarely interact with each other unless it is for territorial or mating purposes. They are mostly lazy animals who bath in the sun during the day and eat whenever necessary. When threatened or scared an iguana will lift its front legs exposing its chest, straighten its spines and expand its dewlap in order to seem larger and more dominant. When interacting with other iguanas for mating purposes they will start to bob their heads for communication. The number of head bobs offer different meanings. This along with the expansion of the dewlap will attract females and promote mating. Because they are independent, they have no social structure and their competitiveness between males is for reproduction purposes only.

Flowers, fruits, leaves, and growing shoots provide an iguana with the correct amount of vitamins and minerals to live a healthy life. They eat the shoots of over 100 different species of plant and seem to not have a preference over one or the other. Iguanas will eat during dawn and dusk when it is not as hot and easy to move around in the humid conditions. They are naturally herbivores, but have been observed eating flying insects and bird eggs under rare conditions. This might be from a lack of specific plant types or possibly a dry season such as La Nina.

Hatchlings are typically 17-25 cm in length and a grown adult can grow up to 2 meters long. Mating rituals are often exhibited through various courtship displays. The egg laying is a long process and can take up to 65 days after mating. A “clutch” of eggs averaging around 20-70. The eggs then take around 90-120 days to hatch and are independent of themselves once out in the open.

An Iguana was seen basking in the sun on a branch over the river.
An Iguana was seen basking in the sun on a branch over the river.

Personal Experience:
As observed in Costa Rica, iguanas were seen as independent reptiles which live their lives at a slow rate with minimal interactions with other organisms. They were seen on top of tree branches over looking river beds and basking in the sun for most of the day. Otherwise they were moving around in grassy areas near the river either basking in the sun or moving from one area to the next. When approached, an iguana exhibited a natural response and stayed still while lifting up its chest seeming bigger than average. They were a greenish brown color, had dewlaps, spines, and black stripes along their tails. None of them were observed eating which might indicate that food was of abundance, or at the wrong time of day.


Packard, Gary and Mary. Phillips, John. Influence of Moisture and Temperature on Eggs and Embryos of Green Iguanas (Iguana Iguana). Herpetologica, pg 238-245. 1990.

Phillips, John. Does cadence of Iguana Iguana displays facilitate individual Recognition? Behavioral Ecology and Sociaobiology. Springer 1995, page 337-342.