Cayman Island blue iguana (Cyclura lewisi)

Also known as: Cayman Island ground iguana, Grand Cayman blue iguana, Grand Cayman iguana
Synonyms: Cyclura nubila lewisi
GenusCyclura (1)
SizeMale snout-to-vent length: up to 51.5 cm (2)
Female snout-to-vent length: up to 41.0 cm (2)

The Cayman Island blue iguana is classified as Endangered (EN) on the IUCN Red List (1), and listed on Appendix I of CITES (3).

Endemic to Grand Cayman, this magnificently striking blue iguana is one of the most endangered lizards on Earth (4). Indeed, at the time of its original description in 1940 the Cayman Island blue iguana was already considered to be on the brink of extinction (5). Blue iguanas normally possess a blue-grey complexion when resting (6) but are better known for the stunning azure blue they turn during the breeding season or when excited (4) (6). The Cayman Island blue iguana is a relatively large iguana (7), with males larger than females (2). Previously listed as the subspecies Cyclura nubila lewisi, this iguana has recently been recognized as a full species, Cyclura lewisi (1).

Once ranging throughout Grand Cayman, this iguana is now found only in the High Rock-Battle Hill area to the east and south of the Queen’s Highway. The unmanaged wild population is sparse and dispersed, and estimated in 2002 at just 10 – 25 individuals (1).

These blue iguanas usually occupy dry evergreen thickets and bush land, as well as man-modified habitats (6) (7). These adaptable iguanas utilize a variety of natural and semi-disturbed habitats in response to temperature needs, food, nesting, predator pressure, and human interference (7).

Females live a solitary life, warning others to stay away from their small territory with vigorous head bobbing gestures (4). Males and females come together only to breed, and, like all Cyclura, breed annually. 1 to 22 eggs are laid depending on the female’s age and size (1), and are then incubated in the nest chamber that is dug about a foot below the surface of the soil (7). Hatchlings are vulnerable to native snakes (Alsophis cantherigerus caymanus) and have a high mortality rate (1).

Primarily herbivorous, these iguanas have been observed to consume 45 different plant species from 24 different families (6) (7). When available, they also feed on fruit, and have even been seen feeding on fungus, crabs, soil, and excrement (7).

Once abundant, the Cayman Island blue iguana has been quietly heading for extinction in the wild since the colonization of the West Indian islands (4). Like other iguana species this beautiful creature is subject to many human-related threats, including: destruction of habitats for farming, residential and commercial developments; road casualties; trapping or shooting by farmers, who perceive iguanas as a threat to their crops; and predation by wild and domestic cats and dogs (4) (7). Large scale deforestation and road construction has also increased enormously in the eastern districts over the last decade, and is only expected to accelerate (7).

The Cayman Island blue iguana is fully protected under local legislation, and kept out of international trade by its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) (1). The National Trust for the Cayman Islands has established an integrated conservation programme incorporating research, habitat protection, captive breeding, re-introduction/restocking, and conservation education (7). These iguanas are being bred successfully in captivity and are subsequently released after two years into the Queen Elizabeth II Botanic Park and Salina Reserve (1) (4). Blue iguana populations in this reserve are being promoted as a major ecotourism attraction, proving beneficial to both the Park and the iguanas (1). It seems that the future of wild blue iguanas must rest on managed populations in protected areas, but suitable land is scarce on Grand Cayman (4). Thus, despite encouraging conservation efforts, the Cayman Island blue iguana still clings to a precarious existence (5), and more protected land must be obtained if there is any hope of securing its future in the wild (4).

For further information on the Cayman Island blue iguanas see:

IUCN Iguana Specialist Group:

Blue Iguana Recovery Program:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (February, 2013)  
  2. (October, 2005)
  3. CITES (October, 2005)
  4. Blue Iguana Recovery Program (October, 2005)
  5. University of Michigan (October, 2005)
  6. Central Florida Zoo (October, 2005)
  7. IUCN Iguana Specialist Group (October, 2005)