Blue Iguana Recovery Program

Sister Isles Rock Iguanas

Sister Isles Rock Iguana - Photo: John Binns

Sister Isles Rock Iguana - Photo: John Binns

The Sister Isles Rock Iguana, Cyclura nubila caymanensis, is native only to Little Cayman and Cayman Brac, and is classified as a subspecies of the Cuban Iguana (Cyclura nubila nubila).

Similar in body form to the Grand Cayman Blue Iguana, this is a large iguana capable of growing to more that 10 kilograms in weight. It varies in colour from almost black through grey or brown, with local highlights in orange, cream and sometimes a little blue, but never blue on the spines or all over the body like the Grand Cayman species.

Once abundant on both islands, the Sister Isles Rock Iguana has been almost wiped out on Cayman Brac, suffering extreme losses to free-roaming dogs and feral cats. Now only a tiny relict population breeds at one location on the southern coast platform, while adults sighted near the public park in West End were probably translocated from Little Cayman (a practice which is now illegal).

On Little Cayman, some 2,000 Sister Isles Rock Iguanas still survive, and they can be seen frequently around the built-up areas in and around South Town (Blossom Village). For all that they appear to have a thriving population, all the pressures that led to the near extinction of the Grand Cayman Blue Iguanas, are now present on Little Cayman. Feral cats have become well established, eating young iguanas before they mature. Domestic dogs are being allowed to run free, threatening breeding adults. Road kills are disturbingly frequent now, and the first large scale habitat destruction is becoming evident as residential subdivisions start to creep across the landscape.

A project led by the Durrell Wildlife Conservation Trust, in partnership with the Cayman Islands Department of Environment and the Blue Iguana Recovery Programme, is currently assessing the risks facing this iguana. We hope to gather information to better plan how to prevent a population crash and avoid the need for another major species recovery effort.

Like the Grand Cayman Blue Iguana, the Sister Isles Rock Iguana is strictly protected under local and international legislation, and should never be handled except for officially authorized conservation work. It is illegal to capture or move iguanas from any of the three Cayman Islands, and it is important to keep the Blues and Sister Isles populations separate on their own respective islands, as they naturally should be.