Green Iguana

The green iguana also called the common or American iguana, is amongst the largest lizard species native to the Americas. Although it is called green, the reptile can be variable in color. It can be distinguished by the pendulous skin under its throat, a row of spines that run along its back and tail, and a long tail that is thinner at the end. This iguana species is also commonly kept as pets in the US even though it requires much effort and care.

Physical Description and Appearance

Size: These large-sized lizards vary in length, with the adults usually growing to 1.2-1.7 m (3.9-5.6 ft). A few large specimens can measure 2 m (6.56 ft) in length.

Weight: Adult males have an average weight of around 4 kg (8.81 lb), and adult females typically weigh between 1.2 and 3 kg (2.6 and 6.6 lb). The largest males can weigh between 6 and 9 kg (13 and 20 lb).

Color: In southern parts of their range, they come in blue color, while the populations on the Caribbean Islands have different colors, ranging from green to black, reddish-brown, and lavender. Green iguanas from the northern parts of their range appear orange while those in the western region are red.

Body: They have a relatively large stature with a well-developed dewlap, a flap of skin, hanging beneath their lower jaw. Green iguanas also have small scales on the back of their head and sharp teeth on the inner side of their jawbone.

Eyes: They have white or cream iris, while some individuals may have yellow irises.

Sexual dimorphism: Males have longer and thicker dorsal spines than the females, while the scent-secreting femoral pores, found on the inside part of their thighs, are larger than those in females.

Distribution

They are native to southern Mexico, Bolivia, central Brazil, Paraguay, and Caribbean Islands, including Trinidad and Tobago, Aruba, Grenada, St. Vincent, St. Lucia, Utila, and Curacao. Some individuals have been introduced to Puerto Rico, Grand Cayman, Dominican Republic, Hawaii, Florida, Texas, and the Virgin Islands.

What Kind of Habitats do Green Iguanas live in

The green iguanas are primarily arboreal, living high up in the canopy of trees that are usually found near water. They also inhabit deep burrows, which they dig in steep riverbanks, canals, dikes, as well as along the seawalls in Florida.

Lifespan

Green iguanas may live for about 20 years in the wild. Captive individuals, on the other hand, have a shortened lifespan, and most of them die within a few years due to improper housing and severe malnourishment. A well-cared iguana may have a life expectancy of 10-20 years in captivity.

Diet

The green iguanas, being herbivores, primarily feed on green leafy plants and ripe fruits. One of the favorite foods of wild iguanas is hog plum. In contrast, the captive ones are given mango, parsnip, and butternut squash. Wild adults occasionally eat grasshoppers, tree snails, birds’ eggs, and carrion.

Behavioral Characteristics

• Green iguanas are arboreal lizards that remain active during the day, most feeding on flowers, fruits, and leaves.
• They are excellent swimmers. When threatened by predators, they may leap from great heights into a waterbody and escape. If cornered, they extend and display their dewlap, distend their body, and bob their head.
• Wounded iguanas are more aggressive than those that are uninjured, and they fight by using their claws, lashing with their tail, and biting the predator.
• Like many lizard species, green iguanas display caudal autotomy, i.e., they can drop a part of their tail when threatened. This behavior startles a predator and gives them the chance to escape.

Adaptations

• The row of dorsal spines extending from their backs to the tails help in protecting them from predators.
• Their whip-like tail is used as a defensive weapon for delivering a painful strike.
• Green iguanas’ eyes have double cone cells, which allow them to see different colors and ultraviolet wavelengths. They can also detect motions and shapes at long distances.
• They have a parietal eye, a photosensory organ that allows them to detect movement in light and dark. It helps them in identifying predators that try to stalk them from above.
• These reptiles have sharp teeth, which they use for shredding leaves.

Mating and Reproduction

Their breeding season starts during the dry summer months, and the hatchlings emerge in the rainy season when food is abundant. The green iguanas exhibit polygynandry, which means both the male and female can have multiple sexual partners. Courtship involves the male bobbing its head, extending and retracting its dewlap, and biting the female’s neck. Males may mark branches, rocks, as well as females with a waxy substance, which is secreted from the femoral pores.

The mating process involves the male approaching the female and climbing on its back. It also restrains the female by gripping the skin with its teeth, causing wounds. The cloacal vents are then paired, with copulation lasting for several minutes. Females lay a clutch of 20-70 eggs about two months after mating. They deposit their eggs in nests that are over a meter deep. Incubation lasts for about 10-15 weeks, after which the hatchlings come out from their nests.

What does the Baby Green Iguana look like

After hatching, young iguanas look similar to adult females to a larger degree than males, lacking dorsal spines. However, they have the same color and shape as that of adults.

Conservation Status

Even though some of the populations have been reduced by poaching, green iguanas, on the whole, are not considered an endangered species. They have been recognized as a ‘Least Concern’ species by the IUCN.

Interesting Facts

• While green iguanas are agile climbers, they often fall from great heights (40-50) and land on the ground without getting hurt. They use their claws to hold onto branches and leaves, thereby breaking a fall.
• These reptiles are excellent swimmers, and they propel through water using their powerful tail. They can remain underwater for about 30 minutes.
• Green iguanas have been regarded as an invasive species in Anguilla, Puerto Rico, Fiji, and South Florida in the United States, where they are a threat to the local ecosystem.