Grand Cayman blue iguana: Back from the brink of extinction

Coordinated by the National Trust for the Cayman Islands, the Blue Iguana Recovery Program—a consortium of local and international partners—has successfully released more than 500 captive-bred reptiles since the initiative's inception in 2002, when the wild population of iguanas numbered less than two dozen.

"For the past several years, we've succeeded in adding hundreds of animals to the wild population, all of which receive a health screening before release," said Dr. Paul Calle, Director of Zoological Health for WCS's Bronx Zoo.

Fred Burton, Director of the Blue Iguana Recovery Program, said: "We expect to reach our goal of 1,000 iguanas in managed protected areas in the wild in a few years. After that, we will monitor the iguanas to make sure they are reproducing in the numbers needed to maintain the wild population. If we get positive results, we will have succeeded."

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Ranging between gray and turquoise blue in color, male iguanas become bluer during the mating season. Credit: Julie Larsen Maher/Wildlife Conservation Society

The Grand Cayman blue iguana is the largest native species of its namesake island, growing to more than 5 feet in length and sometimes weighing more than 25 pounds. The iguana formerly ranged over most of the island's coastal areas and the dry shrub lands of the interior before becoming endangered by a combination of habitat destruction, car-related mortality, and predation by introduced dogs and cats. The entire island's wild population in 2002 was estimated at only 10-25 individuals.

Recovery efforts to save the Grand Cayman blue iguana have mostly centered on the Salina Reserve, a 625-acre nature reserve located on the eastern side of the island. After being hatched and raised for a year or two in a captive breeding facility, each iguana receives a complete health assessment before release. This involves veterinarians taking blood and fecal samples for analysis, as well as weighing and tagging each reptile. The samples are analyzed in a nearby lab at the St. Matthews Veterinary School while sampling continues. The iguanas are released after the lab results are reviewed and health is verified. This year, the recovery program is releasing iguanas into a new protected area, the Colliers Wilderness Reserve, established last year and managed by the National Trust.

Provided by Wildlife Conservation Society