Friday 24 May
Anegada ground iguana (Cyclura pinguis)
What’s the World’s Favourite Species?Find out here.
Anegada ground iguana fact file
- Find out more
- Print factsheet
Anegada ground iguana description
The Anegada ground iguana was once distributed over the entire Puerto Rico Bank but, as its common name implies, its natural range is now restricted to the island of Anegada in the British Virgin Islands (4). This relatively large, stout species of Cyclura has a dusty-brown coloured back and a buff-white to pale grey belly. By contrast, the legs, sides, tail base and dorsal spines are strikingly coloured with varying amounts of brilliant turquoise blue, particularly pronounced in males (2) (4). Juveniles have a grey to moss-green back and sides and are distinctively patterned with a series of wide grey to black forward-pointing chevrons, which fade and are generally lost as the individual matures (2) (4). Eyes are normally a dull yellow, but flush bright crimson when the iguana becomes agitated (2) (4).
- Also known as
- Anegada Island iguana, Anegada rock iguana.
- Cyclure de l'Ile Anegada, Iguane terrestre de l'Ile Anegada.
- Male snout-to-vent length: to 560 mm
- Female snout-to-vent length: to 500 mm
- Male weight: 7.75 kg
- Female weight: 5.25 kg (2)
IUCN/SSC Iguana Specialist Group (ISG):
International Iguana Foundation (IIF):
- A species that lives in trees.
- Having a diet comprising only animal matter.
- Relating to the back or top side of an animal.
- Having a diet comprising only vegetable matter.
- Animals with no backbone.
- Mating with a single partner.
- Puerto Rico Bank
- The islands of Cayo Diablo, St. Thomas, St. John, Tortola, Guana, Greater Camanoe, Necker Cay, Anegada and Virgin Gorda are often collectively referred to as the Puerto Rico Bank.
IUCN Red List (March, 2008)
Cyclura.com (March, 2006)
CITES (January, 2006)
IUCN/SSC Iguana Specialist Group (ISG) (March, 2006)
International Iguana Foundation (IIF) (March, 2008)
The American Zoo and Aquarium Association (AZA) – Significant Efforts in Conservation (March, 2006)
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
Anegada ground iguana biology
The release of livestock on Anegada in 1968 has not only caused a decline in population numbers, but has also had a profound affect on the Anegada ground iguana’s social organisation and diet (2). Estimates in the late 1960s showed the average home range size for iguanas on Anegada to be small, at less than 0.1 hectares, and non-overlapping (2) (4). Additionally, there were roughly equal numbers of males and females, each individual was found to occupy one principle burrow, and habits indicated monogamy, with pairs inhabiting separate but proximate burrows in a joint home range isolated from other pairs. However, by 1991, the sex ratio had changed to two males to every female. Now, home ranges are quite large and overlap, at 6.6 hectares for males and 4.2 hectares for females; with these changes thought to be a result of male competition for far more limited females (4). Males suspected of having a mate have noticeably smaller home ranges, presumed to be due to their greater need to guard the female against wandering bachelors. Females typically lay one clutch of around 12 to 16 eggs per year between May and June, and clutches hatch in August and September at the beginning of the rainy season, when there is greater availability of lush vegetation (2).
Although predominantly herbivorous, the Anegada ground iguana is also an opportunistic carnivore, feeding on invertebrates such as beetles, caterpillars, centipedes and roaches supplementing a diet of leaves and fruit (4). Where the iguana’s range overlaps with feral livestock, the bulk of the diet consists of plants that are rejected by the livestock. These are usually plants containing high levels of secondary compounds that are poorly digested and therefore of poor nutritional value (2).Top
Anegada ground iguana range
The natural range of the Anegada ground iguana has greatly reduced and is now confined to the island of Anegada in the British Virgin Islands (2). In addition two small introduced populations exist on Guana Island and Necker Island. The total population across all three islands is thought to number fewer than 200 individuals (1).Top
Anegada ground iguana habitat
The Anegada ground iguana is closely tied to porous limestone habitats on Anegada, with burrows of both sexes being located on old limestone reef-tract or in sandy areas next to it (4). By contrast, both Guana and Necker are largely volcanic in origin and have few naturally occurring shelter sites, so fewer burrows are used and animals are more arboreal (2).Top
Anegada ground iguana statusTop
Anegada ground iguana threats
Anegada ground iguana populations have undergone a drastic decline in recent decades, leaving possibly fewer than 200 total individuals teetering on the brink of extinction (5). The drop in numbers is probably attributable to a range of threats, including habitat loss and poaching by hunters who are trafficking exotic animals (2). Most devastating, however, has been the introduction of alien species (5). Feral dogs, first reported in 1994, are known to kill adult iguanas, and predation by an exploding population of feral cats on juveniles is responsible for the deaths of many hatchlings each year (2) (5). The primary threat, however, comes from competition for food from feral livestock, with the island teeming with sheep, goats, donkeys and cattle that have been released to roam freely across Anegada (2) (4). Grazing pressure from these livestock has radically changed the composition of vegetation available to the iguana, shifting the species’ diet to rely more on plants with secondary compounds with dubious nutritional value (2).Top
Anegada ground iguana conservation
The Anegada Iguana Recovery Programme began in 1997, which included establishing a ‘headstart’ facility. This facility collects hatchlings and nurtures them in captivity until they can be safely released into the wild, with the aim of combating the high rates of juvenile mortality due to cat predation by raising them until they are large enough that predation will not pose as great a threat (6). The first 24 were released into the wild in October 2003, with an 84 percent survival rate, and a second group of 24 were released in October 2004, and these are currently being tracked (5). In the 1980s, small numbers of these iguanas were removed from Anegada and restored to parts of their former range, on Guana Island, where the species appears to be doing well in the absence of introduced predators (1) (2). The Guana Island Wildlife Sanctuary continues to try to rid the island of sheep, the only feral grazing competitor on the island, which may improve the habitat there for the iguanas (1). The species was also later introduced to Necker Island (2). A national park designed to protect this Critically Endangered iguana on Anegada has been approved in principle by the Anegada Lands Committee, but rampant debates over land ownership and property boundaries impede developments, and must be resolved before this project can progress (2) (4). Further conservation actions advocated include a cat eradication programme and the construction of fences around protected areas to keep livestock out. Indeed, despite the successes of the headstart programme, it is imperative that efforts are made to control livestock and to secure protected land for the survival of this species. Without prompt action, it has been suggested that these iguanas may become extinct on Anegada within the next decade (2).Top
Find out more
For more information on the Anegada ground iguana see:
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:
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.