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iguana

life science Maturity 11-13 Next article →

The genus *Iguana* consists of large, herbivorous lizards found in tropical regions.

Male Green Iguana Belize
Male Green Iguana Belize

These reptiles are native to Mexico, Central America, South America, and the Caribbean. The name "iguana" originates from the Taino word *iwana*. An Austrian naturalist named J.N. Laurenti first described this genus in 1768. Today, iguanas are important members of their ecosystems. They eat leaves, flowers, and fruits. This behavior promotes plant growth and helps with seed dispersal.

Iguana-001
Iguana-001

Because they are large, they often have a high impact on the environments they inhabit.

Iguanas possess several specialized anatomical features for survival. Their bodies are covered in various types of scales. Some are large, round, and tuberculate, while others are small and overlapping. On their cheeks, they have a large, round scale called a subtympanic shield.

Iguana delicatissima au sol
Iguana delicatissima au sol

This shield sits near the tympanum, which is the eardrum. Their vision is very keen. They can see shapes, shadows, colors, and movement from long distances. This visual acuity helps them navigate dense forests and find food. It also allows them to use visual signals to communicate with others.

One fascinating feature is the parietal eye. This is a pale scale located toward the back of the head. It is sensitive to changes in light and sends signals to the pineal gland. This helps the lizard track the transition between day and night. The eye contains a photopigment called parapinopsin. This pigment is sensitive to ultraviolet light. This biological mechanism is vital for regulating their daily cycles. Their muscles also have a unique composition. They contain many fast-twitch, glycolytic muscle fibers. These fibers are low in myoglobin, which makes the muscles appear pale. This allows for quick, short bursts of movement, though it is inefficient for long durations.

Iguanas are strictly herbivorous, meaning they eat only plants.

Iguana iguana eating Mangifera indica from Venezuela
Iguana iguana eating Mangifera indica from Venezuela

To process tough vegetation, they require a high bite force. Their skull morphology has evolved to support this lifestyle. Compared to carnivorous reptiles, iguana skulls are taller, wider, and have shorter snouts. A larger skull allows for more muscle presence and better resistance to force. Their teeth are described as acrodontal. This means the teeth sit on top of the jawbone and project upward. These small, serrated teeth are designed to grasp and shear plant matter.

Green Iguana skull (Iguana iguana) and teeth
Green Iguana skull (Iguana iguana) and teeth

Scientists currently recognize two primary species within the genus. The first is the green iguana (*Iguana iguana*), which is widespread and often kept as a pet.

Cach nuoi rong nam my
Cach nuoi rong nam my

The second is the Lesser Antillean iguana (*Iguana delicatissima*), native to the Lesser Antilles. The green iguana is further divided into several subspecies. These include *I. i. insularis*, *I. i. sanctaluciae*, *I. i. melanoderma*, and *I. i. iguana*. Some researchers believe the green iguana might actually be a complex of multiple species. However, the Reptile Database currently classifies these as subspecies. This taxonomic debate shows how much scientists are still learning about these animals.

Reproduction in iguanas often follows a promiscuous or polygynandrous pattern.

Iguana iguana Portoviejo 01
Iguana iguana Portoviejo 01

Mating typically occurs during the dry season. This timing is strategic so that offspring hatch during the wet season when food is abundant. Females control large territories and create several nests. Males compete for females by marking territory with pheromones from femoral pores. They also use behaviors like head bobbing and changing color to compete. During mating, a male may bite a female's shoulder to hold her in place. This can sometimes leave scars on the female.

After mating, females lay eggs in underground nests. The size of a clutch depends on the female's body size and the environment. A green iguana can lay up to 71 eggs. In contrast, the maximum clutch for a Lesser Antillean iguana is 30. The eggs undergo incubation for more than 85 days before hatchlings emerge. This reproductive method is known as an r-strategy. This means the animals produce many offspring with low levels of parental care. These eggs and hatchlings also serve as a vital protein source for various predators in the wild.

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🖼️ Images & Media (9)
File:Male Green Iguana Belize.jpg
Male Green Iguana Belize.jpg
File:Iguana-001.jpg
Iguana-001.jpg
File:Iguana iguana eating Mangifera indica from Venezuela.jpg
Iguana iguana eating Mangifera indica...
File:Cach nuoi rong nam my.jpg
Cach nuoi rong nam my.jpg
File:Green Iguana skull (Iguana iguana) and teeth.png
Green Iguana skull (Iguana iguana) and teeth.png
Traditional Reptilia.tif
File:Iguana delicatissima au sol.JPG
Iguana delicatissima au sol.JPG
File:Iguana_iguana_Portoviejo_01.jpg
Iguana_iguana_Portoviejo_01.jpg
File:Iguana melanoderma Breuil et al 2020.jpg
Iguana melanoderma Breuil et al 2020.jpg
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