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Blue iguana
- Cyclura lewisi

The Blue iguana (Cyclura lewisi) came to have only between 10 and 25 specimens in the wild.
Blue iguana
Grand Cayman blue iguana (Cyclura lewisi) on rocks – or palsson, CC BY 2.0, via Wikimedia Commons


Origin / Distribution

The Blue iguana (Cyclura lewisi), is endemic to the Caribbean island of Grand Cayman. Formerly they were widespread in the dry and coastal habitats of the entire island., but due to severe habitat loss and predation, now they are only found in the High Rock-Battle Hill area, east and south of the Queen's Highway.

Characteristics / Appearance

The Blue iguana is one of the largest lizards in the Western Hemisphere, as it weighs more than 11 kg and measures more than 1,5 m from head to tail. Males are usually larger than females. The length of the snout can measure up to 51,5 cm in males and 41,5 cm in females, and the tail is of equal length.

The Blue iguana characterized by uniform, stiff dorsal spines and a spineless dewlap. His body is covered in scales, and some enlarged scales are present on the head region. Young iguanas have a gray base color with alternating dark gray and cream chevrons.. as they mature, the youthful pattern fades, and the base color of the hatchlings is replaced by a blue-gray base complexion. Some dark scutes are preserved in adulthood. This blue-gray color is typical of land iguanas when resting. However, these iguanas are best known for the stunning shades of turquoise blue they take on during mating season. For this reason, the Cyclura lewisi is also known as the Blue iguana.

Life expectancy

It is believed that the Blue iguana It is one of the longest living lizard species.. In the wild, they are believed to reach ages of at least 25 to 40 years. However, these iguanas can get much older when kept in captivity. The longest-lived member of this species was a captive iguana known as “Godzilla” that survived to some 69 years. However, it is doubtful that wild iguanas can survive to that age, since Godzilla needed extraordinary maintenance in the years before his death.


Blue iguana
A Blue Iguana at Queen Elizabeth II Botanical Park, Grand Cayman, Cayman Islands – H. Michael Miley from Schaumburg, USA, CC BY-SA 2.0, via Wikimedia Commons

The Blue iguana lives on the ground and can occupy various habitats, like forests, grasslands and coastal regions, as well as human-modified habitats. They are found primarily in natural xerophytic thickets and along interfaces between farm clearings and dry canopy forest.. Farms provide a variety of resources such as vegetation, fallen fruit and soil to nest.

The Blue iguana spends its nights in shelters such as caves and crevices found within weathered rocks, usually heavily eroded limestone. Although iguanas preferentially select the natural rocky substrate to take refuge, they also use artificial shelters such as piles of construction material and spaces under buildings. While adults are mainly terrestrial, younger individuals tend to be more arboreal. Occasionally, the Blue iguana It can take refuge in the hollows of trees or exposed in the branches of the same..


The Blue iguana spend most of the day sunbathing. They are primarily inactive with low to moderate alertness between morning rising and evening retreat.. during activity, iguanas mainly forage, they travel and inspect the substrates, including withdrawals and feces. Iguanas are active for longer periods of time during the summer. Because they are ectothermic, increased sunlight and higher temperatures during the summer allow iguanas to maintain optimal body temperature for a longer period each day.


The Blue iguana it's lonely, except during mating season. Mating is generally polygamous, but some individuals can also be promiscuous or monogamous. During the breeding season, the home range of a dominant male frequently overlaps that of one or more females.

During the breeding season, the Blue iguana takes on a deep blue color. In the spring, hormones spike and males begin to assert their dominance. Males lose weight during this time, since they dedicate their energy to reproduction and to dominating other males. Males expand their territorial range, trying to grab as many female territories as possible. Males in overlapping territories challenge each other and, In most cases, smaller iguanas flee from larger individuals. Physical contact and fights are infrequent and usually limited to individuals of similar size. Fights can be fierce and bloody. the toes, the tips of the tail, crest spines and bits of skin can be torn off in combat.

In March, the abdomen of females Blue iguana It is swollen, since their eggs have formed inside. They do not become receptive to breeding until late April. Females generally avoid males until they begin mating in May., retreating to their holes in the rock when the males are near. Gravid females reduce food intake about two weeks before oviposition, as their digestive tract is compressed by the expanding egg mass. Activity levels also increase during this time.

Copulation is preceded by a mating ritual. The male nods his head and circles behind the female.. Grab the female's neck and try to hold her. The male passes his tail under the female's and positions himself for intromission.. Copulation rarely lasts more than 30 to 90 seconds, and a pair rarely mates more than once or twice a day. Pregnant mature females show a distended abdomen, and the outline of individual eggs can be seen.

At the end of the receiving period, the females of the Blue iguana becomes intolerant of males and drives them out of their territories. The females become so aggressive, in fact, that a female can successfully chase away males much larger than herself.

The Blue iguana lays its eggs in a nest chamber that is excavated about 30 cm below ground surface. while they are in the nest, the eggs absorb moisture from the earth. Little by little they are filled until they are tight and with a slight pressure. On average, the eggs of this iguana are among the largest of all lizards. The eggs hatch in 65 to 100 days, depending on the temperature. The hatching process can take more than 12 hours. The young cut the leathery shell of the egg with a “egg tooth” microscopic at the tip of the jaw.

It takes the combined effort of many hatchlings to get out of the nest chambers.. Times, the Blue iguana does not emerge from next chamber until two weeks after hatching. During this time, the young survive with the rest of the egg yolk stored in their abdomen. They can live on the remains of the yolk for weeks before needing to feed or drink..

Young iguanas are independent after hatching. They are usually arboreal and spend most of their young lives in trees to avoid terrestrial predators..

The breeding season of the Blue iguana hard of 2 to 3 weeks, between the end of May and mid-June. Oviposition occurs approximately 40 days after fertilization, usually during the months of June and July. The females lay from 1 to 22 eggs every year. The size of the clutch varies with the age and size of the females. Older and larger females are able to produce more eggs. The eggs are incubated in the nest chamber that is dug to some 30 centimeters below the soil surface. The incubation period ranges from 65 and 90 days. The temperature inside the nest remains relatively constant between 30 and 33 degrees Celsius throughout this period. The Blue iguana it usually begins to reproduce around the 4 years of age in captivity. In the wild, reach sexual maturity among the 2 and 9 years of age.

(Blair, 1991; Burton, 2009; Blue Iguana Recovery Program, Grand Cayman, Cayman Islands, British Indies”, 2011)


The Blue iguana is mainly herbivorous, consuming mainly vegetable matter of at least 45 plant species of 24 different families. The leaves and stems are the most consumed, while the fruits, nuts and flowers are consumed in less quantity. Carnivory makes up a small percentage of the diet. This includes predation on invertebrates such as insects, slugs and moth larvae. Specimens of iguanas have also been observed ingesting small rocks, tierra, feces, pieces of molt and mushrooms.

Threats to the species

State of conservation ⓘ

Endangered in danger ⓘ (UICN)ⓘ

The Blue iguana it is one of the fastest disappearing and endangered species on Earth. The decline of these iguanas on Grand Cayman probably began in pre-Columbian times., when they were hunted for food by the native Indians of the Arawak and Lucayan tribes. The most serious decline began with the European colonization of the Cayman Islands. As the human population increased, habitat was cleared for agriculture and the construction of homes and businesses. In the news, Habitat loss is the main factor threatening the extinction of the Blue iguana. Vehicle road construction has led to further habitat destruction and has brought fast-moving traffic to remnant habitats. This occasionally results in his death from vehicles.

(Blair, 1991; Burton, 2004to; “ARKive Images of Life on Earth”, 2011)

Another great threat associated with European colonization was the introduction of invasive species on the island., like cattle, the goats, the pigs, the rats, cats and dogs. The Blue iguana faces predation or competition from these introduced animals. Less often, iguanas can be illegally trapped or shot by farmers who perceive the iguanas as a threat to their crops.

(Blair, 1991; Burton, 2004to; Burton, 2009; “ARKive Images of Life on Earth”, 2011)

The National Trust for the Cayman Islands established the Recovery Program Blue iguana in 1990. This conservation program incorporates research, habitat protection, captive breeding, reintroduction and conservation education. Despite the protection of 2000 acres of dry mangrove forests and wetlands within the Cayman Islands, protected lands suitable for Blue iguana they are very scarce.

(“Blue Iguana Recovery Program, Grand Cayman, Cayman Islands, British Indies”, 2011; Burton, 2004to)

The Recovery Program Blue iguana has successfully bred this species in captivity since 1990. Members of this species breed to 2 years old and are released at the Queen Elizabeth II Botanic Park in Grand Cayman. These young iguanas help complement existing wild populations and also establish new wild populations in protected areas..

(“Blue Iguana Recovery Program, Grand Cayman, Cayman Islands, British Indies”, 2011; Burton, 2004to)

The Blue iguana is fully protected by local law and is considered critically endangered by the IUCN. It is illegal to kill, capture or keep members of this species in captivity. It also, international trade in this species is prohibited, as it is included in Appendix I of the Convention on International Trade in Endangered Species (CITES).

(Burton, 2004to; “ARKive Images of Life on Earth”, 2011)

This species of intense blue color came to have only between 10 and 25 specimens in the wild.
Currently, after years of intensive work, have already been released near 500 captive-bred specimens.

The "Blue iguana" in captivity

The Blue iguana served in his day as food to the natives of the island. In the news, this species is a great attraction for ecotourists. Times, the Blue iguana is captured illegally, sold and kept as a pet.

Buy one "Blue iguana"

If we make inquiries on the Internet related to where or how to buy a Blue iguana, we will find that the search engine shows us some results.

Devoting a few minutes to reviewing these results we can see that they are mostly other species, put up for sale as blue iguanas.

In some cases it may be due to the seller's own ignorance, who does not know how to differentiate between the different species of iguanas. In others, it can be directly a malicious deception.

Even if they were actual specimens of Blue iguana and regardless of the price they ask for them, we must not forget that it is a species in serious danger of extinction.

Videos "Blue iguana"

Alternative names:

    1. Blue iguana, Grand Cayman ground iguana, Grand Cayman blue iguana, Cayman Island rock iguana (English).
    2. Iguane bleu (French).
    3. Blauer Leguan, Grand-Cayman-Leguan (German).
    4. Iguana-azul, Iguana-da-grande-caimão (Portuguese).
    5. "Iguana azul" (español).
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