Report submitted by Jeff Lemm, San Diego Zoo
The San Diego Zoo’s Conservation and Research for Endangered Species (CRES) is pleased to announce the hatching of three Grand Cayman Blue Iguanas. The hatchlings emerged from their eggs over a 3-day period from September 17–19, 2007. The mother, who weighed only 550 grams, nested four eggs in the soil of a potted Hibiscus plant at CRES. The nesting and hatching dates are similar to those for iguanas in Grand Cayman. The eggs each weighed an average of 56.5 grams and measured 66 mm long by 45 mm wide. The eggs were placed on a mixture of vermiculite and water at a ratio of 1:1 by weight, and incubated at a temperature of 30° C. The first iguana pipped after 83 days of incubation. The hatchlings weighed an average of 44.2 grams and measured 97 mm from snout-to-vent (SVL).
The Grand Cayman Blue Iguana (Cyclura lewisi) is considered by many to be the most endangered lizard in the world. Threats include severe habitat loss and fragmentation, road traffic, and intense predation from non-native feral and domesticated animals. The Blue Iguana Recovery Program was developed among several international collaborators to reverse the iguana’s path to extinction by headstarting, breeding, and releasing iguanas within protected reserves in Grand Cayman. To date, over 250 iguanas have been released and the prospect for species survival is slowly improving. One of the many program goals is to develop a self-sustaining ex situ captive population that mirrors the genetic diversity of the remaining wild population and provides a hedge against catastrophic loss in Grand Cayman.
The dam hatched in 2001 at the headstart and breeding facility in Grand Cayman and she and the sire (hatched 2002) were brought to CRES in 2005. This pair, along with eight other juveniles representing five founder pedigrees new to the U.S. captive population, was imported by the International Iguana Foundation in order to bolster the genetic diversity of the breeding program. This is the first breeding of this species at San Diego; only two other zoos (Gladys Porter and Indianapolis) have bred Blue Iguanas in the U.S. in the last decade. CRES has been an integral part of the AZA’s Cyclura SSP (American Zoo and Aquarium Association Species Survival Plan) since its inception and is a collaborator on the Blue Iguana Recovery Project.