Blue Iguana

Blue Iguana

Grand Cayman ground iguana, Grand Cayman blue iguana, Cayman Island rock iguana, Grand cayman ground iguana, Grand cayman blue iguana, Cayman island rock iguana

Cyclura lewisi
Population size
Life Span
20-40 years
kg lbs 
m ft 

The blue iguana (Cyclura lewisi ), also known as the Grand Cayman ground iguana, Grand Cayman blue iguana or Cayman Island rock iguana, is an endangered species of lizard which is endemic to the island of Grand Cayman. It was previously considered to be a subspecies of the Cuban iguana, Cyclura nubila, but in a 2004 article Frederic J. Burton reclassified it as a separate species because according to him the genetic differences discovered four years earlier between the different C. nubila populations warranted this interpretation. The blue iguana is one of the longest-living species of lizard (possibly up to 69 years).

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The preferred habitat for the blue iguana is rocky, sunlit, open areas in dry forests or near the shore, as the females must dig holes in the sand to lay eggs in June and July. A possible second clutch is laid in September. The blue iguana's herbivorous diet includes plants, fruits, and flowers. Its color is tan to gray with a bluish cast that is more pronounced during the breeding season and more so in males. It is large and heavy-bodied with a dorsal crest of short spines running from the base of the neck to the end of the tail.

The iguana was possibly abundant before European colonization; but fewer than 15 animals remained in the wild by 2003, and this wild population was predicted to become extinct within the first decade of the 21st century. The species' decline is mainly being driven by predation by cats and dogs, and indirectly by reduction in suitable habitat as fruit farms are converted to pasture for cattle grazing. Since 2004, hundreds of captive-bred animals have been released into a preserve on Grand Cayman run by a partnership headed by the Durrell Wildlife Conservation Trust, in an attempt to save the species. At least five non-profit organizations are working with the government of the Cayman Islands to ensure the survival of the blue iguana.

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The Blue iguana is an endangered species of lizard that is native to the island of Grand Cayman. This large lizard has articulated toes that are efficient in digging and climbing trees. The mature male's skin color ranges from dark grey to turquoise blue, whereas the female is more olive green to pale blue. Young animals tend to be uniformly dark brown or green with faint darker banding. Adults change their color to blue when they are in the presence of other iguanas to signal and establish territory. The blue color is more pronounced in males of the species. Males are also larger and have more prominent dorsal crests as well as larger femoral pores on their thighs, which are used to release pheromones.



Biogeographical realms

Blue iguanas can be found throughout the island Grand Cayman excluding the urban areas of Bodden Town, Gun Bay, Seven Mile Beach, and West Bay. They now only occur inland in natural xerophytic shrubland and prefer rocky, sunlit, open areas in dry forests or near the shore. They can also be found along the interfaces between farm clearings, roads, and gardens.

Blue Iguana habitat map

Climate zones

Blue Iguana habitat map
Blue Iguana
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Habits and Lifestyle

Blue iguanas are solitary creatures and come together only to breed. They are active during the day and sleep at night in rock holes and tree cavities. As adults Blue iguanas are primarily terrestrial although they may climb trees 15 feet (4.6 m) and higher. Younger individuals tend to be more arboreal.

Seasonal behavior

Diet and Nutrition

Blue iguanas are herbivorous (folivorous, frugivorous). They consume leaves, flowers, and various fruits. They may very rarely eat insects, crabs, slugs, and fungi.

Mating Habits

40 days
65-90 days
1 to 22
0 minutes
1-21 eggs

Blue iguanas breed from May through June. The male courts the female by numerous head-bobs and then he circles around behind the female and grasps the nape of her neck. About 40 days after mating the female excavates a nest in pockets of earth exposed to the sun and lays there a clutch of anywhere from 1 to 21 eggs, usually in June or July. The temperature within nests that have been monitored by researchers remained a constant 32 °C (90 °F) throughout the incubation period which ranges from 65-90 days. The young are aggressively territorial from the age of about 3 months onward. They typically reach reproductive maturity after 4 years of age in captivity.


Population threats

The Blue iguana was possibly abundant before European colonization, however, by 2003 fewer than 15 animals remained in the wild; this wild population was predicted to become extinct within the first decade of the 21st century. Habitat destruction is the main factor threatening extinction for this iguana. Land clearance within a remnant habitat is occurring for agriculture, road construction, and real estate development and speculation. The conversion of traditional croplands to cattle pasture is eliminating secondary Blue iguana habitat. Predation and injury to hatchlings by rats, to hatchlings and sub-adults by feral cats, and the killing of adults by pet dogs are all placing severe pressure on the remaining wild population. Automobiles and motorscooters are another increasing cause of mortality as the iguanas rarely survive collisions.

Population number

According to the IUCN Red List, the total population size of the Blue iguana is 443 mature individuals. Currently, this species is classified as Endangered (EN) on the IUCN Red List but its numbers today are increasing.

Fun Facts for Kids

  • The Blue iguana is one of the longest-living species of lizard.
  • The closest relatives of the Blue iguana are the Cuban iguana and the Northern Bahamian rock iguana.
  • The name "blue iguana" is also used for bright blue forms of the Green iguana.
  • The Blue iguana is among the largest species of lizard in the Western Hemisphere.
  • Blue iguanas have red eyes adapted to protect pupils from the sun’s glare.
  • The Blue iguana's eggs are among the largest laid by any lizard.
  • In 2006 the Blue iguana was one of the most endangered lizards on Earth.

Coloring Pages


1. Blue Iguana on Wikipedia -
2. Blue Iguana on The IUCN Red List site -

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