Iguana

Iguanas are stout lizards living in the tropical parts of the western world. They are identified from their bulky appearance, scaly skin covered in warts, spines on their back, and a flap of flesh under their necks. The name “iguana” comes from the Taino word iwana, which refers to the creature in the Caribbean. 

Scientific Classification

Animalia
Chordata
Reptilia
Squamata

Scientific Classification

Animalia
Chordata
Reptilia
Squamata

Due to their distinct appearance and gentle nature, these lizards are popular pets in the US. However, several iguana species are endangered in the wild, with some at the risk of extinction.

Types of Iguana

List of the Common Types of Iguana Species

There are over 35 recognized species of iguana, divided across 8 genera.

  • Marine Iguana
  • Green Iguana
  • Lesser Antillean Iguana
  • Lau Banded Iguana
  • Gau Iguana
  • Fiji Crested Iguana
  • Campeche Spinytail Iguana
  • Yucatán Spinytail Iguana
  • Galapagos Land Iguana
  • Galapagos Pink Land Iguana
  • Santa Fe Land Iguana    
  • Northeastern Spinytail Iguana
  • Utila Spinytail Iguana
  • Balsas Armed Lizard
  • Yellowback Spinytail Iguana
  • Cape Spinytail Iguana
  • Honduran Paleate Spinytail Iguana
  • Oaxacan Spinytail Iguana
  • Roatán Spinytail Iguana
  • Guatemalan Spinytail Iguana
  • Club Tail Iguana
  • Black Spinytail Iguana
  • Turks and Caicos Rock Iguana
  • Jamaican Iguana
  • Rhinoceros Iguana
  • Northern Bahamian Rock Iguana
  • Grand Cayman Blue Iguana
  • Cuban Rock Iguana
  • Anegada Ground Iguana
  • Ricord’s Iguana
  • San Salvador Iguana
  • Mona Ground Iguana    
  • Desert Iguana
  • Catalina Desert Iguana                  
  • Common Chuckwalla
  • Angel Island Chuckwalla
  • Monserrat Chuckwalla
  • San Esteban Chuckwalla
  • Spotted Chuckwalla
  • Central Fijian Banded Iguana

Iguana
Iguana Picture

Physical Description and Appearance

Size: Length: 5 to 6 ft (1.5 to 1.8 m)

Weight: 2.6 to 30 lbs. (1.17 to 13.6 kg)

Body and Coloration: Iguanas are generally heavily built lizards. A typical physical feature among them is the presence of a fleshy flap below their lower jaw called a dewlap. There is also a row of elongated scales that run from their necks to their tails. The iguana’s body is scaly, with the dorsal scales being thicker and tightly packed than the ventral ones. A large, round scale on their cheeks is called a subtympanic shield. Iguanas have 80 to 120 individual teeth at any time.

They have shown various color morphs, the common ones being green, blue, and grey. For instance, the green iguana shows a vibrant green color, while spinytail iguanas are a whitish grey.

Where are they found

These lizards reside in Central America, the Caribbean, Mexico, and South America. For example, chuckwallas are found in the Sonoran and Mojave deserts, while the rhinoceros iguana lives in the Dominican Republic.

Habitat

Iguanas live in various habitats depending on the species. These include deserts, lowlands, rainforests, rocky regions, and swamps.

Iguana Habitat
Iguana Image

How long do they live

Most iguanas have an average lifespan of 10-20 years in the wild.

What do they eat

Most iguanas are herbivorous, eating leaves, fruits, and flowers. However, some iguana species, like the spinytail iguana, are omnivorous and eat insects like the wax worm as well. Some species have bacteria in their guts, fermenting the plant material they eat.

Behavior

  • They are diurnal and can be seen feeding during the day.
  • Iguanas are social creatures and live close to one another. However, males are territorial and chase out other males who invade their territory.
  • These lizards try to warn intruders by bobbing their heads and shaking its dewlap as a form of intimidation.
  • Migration is often observed in iguanas, with some traveling up to 3 km searching for a potential nesting site. 
Iguanas
Full Grown Iguana

Predators

The natural enemies of the iguana include birds of prey like hawks and owls, raccoons, and snakes.

Adaptations

  • Their sharp teeth help them chew plants efficiently, and their strong jaws allow them to use those teeth to deliver a powerful bite.
  • Like several other species of lizard, iguanas can detach their tails as a distraction. The tails grow back after some time.
  • They have a pale scale at the back of their heads, which marks the parietal eye. This organ is light sensitive, sending signals to the pineal gland to distinguish the day-night transition.

How do they reproduce

Iguanas tend to be promiscuous, with females mating with multiple partners during the dry season. This ensures that the baby iguanas will be born during the rainy season. Males compete for mates by bobbing their heads, extending and retracting their dewlaps, and changing their color. Once the female chooses a mate, the male climbs on her, bites onto her shoulder, and begins to copulate.

Iguana Eggs
Iguana Lizard

Life Cycle

The eggs are laid in several nests and allowed to incubate. Once they hatch after 10-14 weeks, the parents have minimal involvement, though they watch over the young for a few months. The juveniles reach sexual maturity in 1.5-2 years.

Conservation

According to the IUCN, iguanas are some of the most endangered animals globally, with their numbers dropping drastically due to habitat loss and predators. For instance, the Galápagos pink land iguana is labeled as “critically endangered” or “CR”, as is the Utila spiny-tailed iguana.

Iguanas– FAQs

1. Are iguanas dangerous?

No, they are not dangerous to humans and only bite if threatened. While they do possess venom, it is weak and not dangerous to humans.

2. Do iguanas get hurt when they fall from trees?

Some iguanas, like the green iguana, are capable of falling from a height of 40 ft and surviving. This happens more often in colder temperatures below 40⁰F where iguanas become immobile and are unable to maintain their grip on trees. As cold-blooded creatures, they freeze and fall into a coma.

3. Can iguanas swim?

Yes, they are excellent swimmers. Most notably the marine iguana uses their flat tail to move about underwater in a serpentine fashion.

4. What is a group of iguanas called?

A group of iguanas is called a mess. This is because when in a group, it is difficult to tell individual iguanas apart.

Picture of a Iguana
Iguana Eyes

Interesting Facts

  • The iguana is a popular pet, owing to the fact that they are docile and relatively easy to maintain.
  • In parts of Central America, iguanas are often reared for their meat. Their eggs are also consumed in countries like Columbia and Nicaragua.