The American iguana, also known as the green iguana, is a large, primarily herbivorous lizard native to Central and South America, ranging from southern Mexico to Brazil and Paraguay. It also inhabits many Caribbean islands and has been introduced to parts of Florida, Hawaii, and other tropical regions, where it thrives in both wild and urban environments.
Adults can grow to impressive lengths of 1.2 to 2 meters (4 to 6.5 feet), including the tail, and may weigh up to 5 kg (11 lbs). Despite the name “green iguana,” their coloration varies widely with age and region—from bright green in juveniles to gray, orange, or brown in mature adults. Males develop prominent physical features including a large dewlap (throat fan), dorsal spines, and jowls, which they use in territorial and mating displays.
Green iguanas are diurnal and arboreal, spending much of their time in the treetops near rivers or wetlands. They are strong swimmers and will often dive into water to escape predators. Their long, whip-like tail is used for defense, and they can deliver sharp bites with their serrated teeth if threatened.
Their diet consists mainly of leaves, flowers, and fruits, though juveniles may occasionally consume insects. As herbivores, they play a role in seed dispersal in forest ecosystems.
Reproduction is oviparous, with females laying 20–70 eggs in sandy burrows. Hatchlings emerge after about 90 days and are fully independent. In regions where they are invasive, green iguanas can damage gardens, infrastructure, and native plant life.
The American iguana’s scientific name is Iguana iguana, and it belongs to the family Iguanidae.
The American Iguana is a large, tree-dwelling lizard native to Central and South America, and now common in parts of the southern United States and the Caribbean. Known for its crest of spines, dewlaps, and long tail, it is one of the most recognizable iguanids in the world.
Coloration:
Despite the name “Green Iguana,” coloration varies with age and location. Juveniles are typically bright green, while adults may be grayish-green, orange, brown, or even bluish. During mating season, males often display intense orange or rusty hues, especially on the legs, dewlap, and spines.
Head and Eyes:
They have a large, angular head with pronounced cheek scales and a large, circular subtympanic shield behind the jaw. The eyes are set laterally with round pupils and excellent color vision.
Dewlap:
A prominent dewlap (throat fan) hangs below the jaw and can be extended to regulate temperature, signal dominance, or deter predators.
Body and Scales:
The iguana’s body is robust and muscular, covered in rough, overlapping scales. A row of tall, spiny dorsal crestsruns from the back of the head down to the tail, more prominent in males.
Tail:
The tail is very long—often longer than the body itself—and laterally compressed. It is used for balance, swimming, and defense, capable of delivering sharp, whipping blows when threatened.
Limbs and Toes:
They have strong limbs with sharp claws for climbing. Their long toes and strong grip make them excellent arboreal reptiles.
Size:
Total Length: 4 to 6.5 ft (1.2 to 2 m), including tail
Snout-to-Vent Length (SVL): 1.5 to 2.5 ft (45 to 76 cm)
Weight:
Adult iguanas typically weigh 4 to 10 kg (9 to 22 lbs), with males being larger and more muscular than females.
The American Iguana’s impressive size, bright coloration, and arboreal adaptations make it a distinctive figure in tropical forests, urban landscapes, and the exotic pet trade.
The American Iguana has a seasonal reproductive cycle strongly influenced by temperature, daylight, and rainfall. Its reproductive strategy involves territorial mating behavior, large clutch sizes, and delayed nesting, allowing hatchlings to emerge during peak food availability.
1. Mating and Seasonality:
Breeding typically occurs during the dry season (often December to February in tropical regions).
During this period, males become highly territorial, displaying head bobs, dewlap extensions, and vibrant coloration (especially orange or rust hues).
Male combat is common, with rivals engaging in push displays and bites to establish dominance.
2. Copulation:
Once a female accepts a male’s advances, copulation occurs through cloacal contact.
The process may last several minutes, and males may mate with multiple females during the breeding season.
3. Egg-laying:
About 65 to 90 days after mating, the female lays eggs in a self-dug burrow, usually in sandy or soft soil with good drainage and sun exposure.
Clutch Size: Ranges from 20 to 70 eggs, depending on the female’s size and health.
Eggs are leathery and white, measuring about 1.5 in (4 cm) in length.
4. Incubation and Hatching:
Incubation lasts approximately 10 to 14 weeks (around 90 to 120 days).
Hatchlings emerge in the early rainy season, when plant growth and food are abundant.
Hatchlings are independent at birth and receive no parental care.
5. Sexual Maturity:
American iguanas reach sexual maturity at around 2 to 4 years of age, with males typically maturing slightly later than females.
This reproductive strategy—high egg output, synchronized hatching, and early independence—has allowed the American Iguana to thrive in both its native and invasive ranges.
The American Iguana is a long-lived reptile with a lifespan that varies widely based on habitat quality, predation risk, and human interaction. In both the wild and captivity, their longevity is influenced by access to food, warmth, and protection from disease and injury.
Lifespan in the Wild:
In natural tropical habitats such as rainforests, riverbanks, and mangrove swamps, wild iguanas typically live 8 to 12 years. Juvenile mortality is high due to predation by birds, snakes, mammals, and even other iguanas, but adults that survive their early years can live well over a decade.
Lifespan in Captivity:
In zoos, sanctuaries, and responsible private care, American Iguanas can live 15 to 20 years, and in rare cases up to 25 years. Proper diet, lighting (UVB), enclosure size, and veterinary care are essential to achieving maximum lifespan in captivity.
Threats to the American Iguana:
Predation: Eggs and juveniles are vulnerable to many predators, including coatis, hawks, and rats. Adults face fewer threats but may be hunted by large snakes and humans.
Human Conflict: In both native and invasive ranges, iguanas may be hunted for food or culled due to property damage. In urban areas, they’re often hit by vehicles or trapped in buildings.
Habitat Loss: Deforestation and urban sprawl reduce nesting sites and access to safe basking areas.
Health Issues in Captivity: Inadequate UVB lighting, calcium imbalance, dehydration, or small enclosures can cause metabolic bone disease and premature death.
Despite these risks, the American Iguana’s resilience, adaptability, and long reproductive window contribute to stable populations in many parts of its native and introduced range.
The American Iguana is primarily herbivorous, with a digestive system adapted to breaking down tough plant matter. While juveniles may consume some animal protein, adults feed almost exclusively on vegetation. Their diet plays a vital role in both rainforest ecology and their long-term survival.
Diet:
Adult American iguanas feed on a wide range of leaves, flowers, fruits, and shoots, including:
Hibiscus and bougainvillea leaves
Papaya, mango, and banana fruits
Fig tree leaves
Dandelion greens, squash blossoms, and mulberry leaves
Juveniles may occasionally eat:
Insects (like grasshoppers or ants)
Small lizards or eggs (opportunistically)
Carrion (rarely)
Feeding Strategy:
Arboreal Foraging: Iguanas climb trees and shrubs to access new shoots and soft leaves, often spending hours grazing in sunlit canopies.
They use their strong jaws and serrated teeth to tear fibrous plant material.
Iguanas are diurnal feeders, consuming food during daylight, especially in the morning after basking.
Digestive Adaptations:
Iguanas rely on gut microbes in their large intestine to ferment and digest cellulose.
Because of their slow metabolism, they can survive on low-calorie food but require consistent plant intake to maintain health.
Water Intake:
Iguanas hydrate primarily through moisture in fruits and leaves, but they also drink from puddles, streams, and rain droplets.
In captivity, they benefit from misting, water bowls, and high-moisture greens.
Feeding in Captivity:
Captive iguanas require a calcium-rich, low-oxalate diet made up of dark leafy greens, squashes, and limited fruit. Animal protein should be avoided in adults, as it can lead to kidney damage.
The American Iguana’s plant-based diet, arboreal grazing habits, and digestive specialization make it one of the most ecologically significant herbivorous reptiles in tropical forest systems.
The American Iguana is one of the largest, most recognizable lizards in the Western Hemisphere. Its prehistoric appearance, herbivorous diet, and tree-dwelling lifestyle distinguish it among reptiles—and contribute to both its ecological importance and its popularity (and notoriety) in human environments.
Arboreal Herbivore with a Dinosaur Look:
Few reptiles combine the size, crest, and color of the American Iguana. Its dragon-like spines, long whip-like tail, and leaf-only adult diet make it one of the few large, fully herbivorous, tree-dwelling lizards on Earth.
Thermoregulation Through Color and Behavior:
Iguanas bask in the sun to regulate their body temperature, often lying flat on warm surfaces with their dewlap extended to absorb heat. Juveniles tend to be bright green for camouflage, while mature males may turn orange during breeding season to display dominance and attract mates.
Excellent Swimmers and Escapers:
Though largely arboreal, iguanas are strong swimmers. When threatened, they may leap from trees into rivers, using their long tails for propulsion. They can also hold their breath for up to 30 minutes, helping them evade predators underwater.
Dewlap Communication and Social Displays:
The dewlap serves more than thermoregulation—it’s used in visual communication, including territorial warnings, courtship, and defensive displays. Iguanas also use head bobbing sequences to signal social rank or assert dominance.
Invasive Impact in Non-native Areas:
Introduced populations in Florida, Puerto Rico, and other islands have become invasive, damaging gardens, native plants, and infrastructure. Their reproductive success, burrowing, and herbivory have made them a management challenge in urban and coastal regions.
Cultural and Commercial Icon:
The American Iguana has become a symbol of exotic wildlife—commonly kept as a pet, featured in zoos, and depicted in tropical culture. However, improper care and abandonment have led to concerns about welfare and ecological disruption.
The American Iguana’s combination of prehistoric beauty, ecological role, and global visibility makes it one of the most distinctive and controversial reptiles in the Americas.
The closest species to the American Iguana is the Lesser Antillean Iguana (Iguana delicatissima) and the Black Iguana(Ctenosaura similis), though the latter belongs to a different genus.
Within the genus Iguana, I. delicatissima is genetically and morphologically closest, found primarily in the Lesser Antilles.
These species differ in coloration, scale structure, and range. Unfortunately, I. iguana has hybridized with and displaced some native I. delicatissima populations in the wild.
Iguanas differ from other lizards in several ways:
Size: It is one of the largest iguanid lizards, reaching up to 6.5 ft (2 m), much larger than most arboreal lizards.
Diet: Unlike many omnivorous or carnivorous lizards, it is strictly herbivorous as an adult, feeding primarily on leaves, flowers, and fruit.
Behavior: It is both arboreal and diurnal, with a strong dependence on sunlight for thermoregulation. It is generally non-aggressive but will defend itself with powerful tail whips and bites.
Reproductive Output: It lays large clutches of eggs—often 20–70—making it highly successful in warm, tropical regions.
Ecological Impact: In invasive regions, it causes widespread damage to vegetation, gardens, sea walls, and native ecosystems, unlike many native lizards that occupy more narrow niches.
The American Iguana is native to Central and South America but has also been introduced in many regions. It is common in lowland tropical parks and reserves, particularly in sunny, riverine, or coastal areas. Top parks for spotting wild iguanas include:
Tortuguero National Park (Costa Rica):
– Common along riverbanks, canals, and forest edges.
Corcovado National Park (Costa Rica):
– Often seen basking in trees near water or open clearings.
Manuel Antonio National Park (Costa Rica):
– Frequently encountered by visitors along trails and beaches.
Tambopata National Reserve (Peru):
– Arboreal iguanas seen along riverbanks and in tree canopies.
El Yunque National Forest (Puerto Rico):
– Invasive populations commonly seen in open sunny areas.
Everglades National Park (Florida, USA):
– Invasive iguanas thrive in canal zones, mangroves, and picnic areas.
Because of their size, diurnal habits, and fondness for basking, iguanas are easy to spot, especially in sunny areas near water or tree clearings.
