Captive Management Guidelines:
Cyclura
Captive programs are currently in place for five taxa of rock iguanas. In addition to the captive rearing program at the Hope Zoo in Jamaica, a satellite program for Jamaican iguanas in the U.S. has recently been instituted, with 2.2 individuals each at the Fort Worth and Gladys Porter zoos, 1.2 individuals each at the Indianapolis, Central Florida, and Sedgwick County Zoos, and 3.3 individuals at the San Diego Zoo's Center for Reproduction of Endangered Species. In collaboration with the National Trust for the Cayman Islands, a program for the Grand Cayman iguana is also currently underway, involving animals at the Bermuda Aquarium, the John G. Shedd Aquarium, and the Indianapolis, Central Florida, and Burnett Park Zoos. North American captive populations of both taxa will be managed under the American Zoo and Aquarium Association's first lizard Species Survival Plan. A small number of Ricord's iguanas (1.3) at the Indianapolis Zoo are being managed as part of a cooperative program with Zoodom in the Dominican Republic. Although Cuban iguanas and rhinoceros iguanas are widely held in North American collections, the primary purpose of these programs is for research and education rather than captive breeding.
Housing
Rock iguanas are large lizards that need a fair amount of space devoted to them as adults. A minimum of 10m2 is recommended for an adult pair. This space coupled with several visual barriers allows adequate room and minimizes territorial aggression. Rock iguanas can be kept in groups if enough space is provided, although they are very territorial and a dominance hierarchy will quickly emerge. With the exception of Ricord's and rhinoceros iguanas, which are naturally sympatric, the other species of rock iguanas should remain separated. Equally important to the housing arrangement are secure hide areas to which each animal has exclusive access. They may not each use a separate hide, but it is important that it be available. They will use these hides to escape conspecific aggression and to retire for the evening.
Cork bark tubes provide hide areas for juvenile iguanas at the Hope Zoo, Kingston, Jamaica.
Ideally, iguanas should be housed outdoors, thereby providing access to natural sunlight. Year-round outdoor maintenance is preferable, with attached, heated, indoor holding for cooler periods. Care must be taken to prevent the iguanas from digging out of the enclosure. A 2.5cm x 2.5cm wire mesh is adequate for containment. A natural substrate of sand, gravel, turf or a mixture of these components is preferable. If breeding is expected, then a nest area with adequate drainage is required. As large an area as possible should be provided as female rock iguanas can dig extensive nest tunnels and chambers.
Successful maintenance of rock iguanas can be accomplished in temperate climates through movement outdoors in warm summer months. Although moving the animals in this way has been successful for maintaining and even breeding some species of rock iguanas, this method may be too stressful for long term reproduction programs. Moving animals during critical breeding or egg-laying periods should be avoided. Rock iguanas can be maintained indoors, providing that all the above parameters are met. Accessible artificial UV light within 50cm above a basking site should be provided. Temperature gradients within iguana enclosures should range up to 40°C.
Nutrition
Rock iguanas are primarily herbivorous. Captive specimens maintained properly will feed on a wide variety of fruits, vegetables, leafy greens as well as various sources of protein. Dry, leafy, alfalfa hay may be accepted by some rock iguanas as browse. The animal protein component should make up only about 5% of the diet. Some juveniles will feed readily on insects and may have larger percentages of protein in their diet. As adults, rock iguanas seem to be opportunistic predators and will readily take meat if offered. Food should be offered to these browsers daily, although care must be taken to prevent obesity. Providing a varied diet is important and use of seasonally available produce helps maintain a lively feeding response. The addition of a powdered multivitamin and a calcium source two to three times weekly is recommended. Although they are rarely observed drinking, rock iguanas should have access to a water source.
Health
Rock iguanas are extremely healthy, long-lived animals when cared for properly. Endoparasites can be easily treated with various anti-helminthic agents, to which the animals generally respond very well. Ectoparasites can be treated by standard methods. Conspecific aggression can result in physical injuries to iguanas. Although these are usually minor scrapes or cuts, occasionally more serious injuries result which require suturing and antibiotic treatment.
Breeding
Several species of rock iguanas have bred successfully in captivity, particularly rhinoceros and Cuban iguanas. Successful reproduction can occur with single, adult pairs in an enclosure. Combat behavior could be an important stimulus for reluctant males, and if space allows, rock iguanas should grouped to allow for pair bonding and male combat. In captivity, rock iguanas are annual, seasonal breeders. Breeding usually takes place in the spring or summer, and hatching in the fall. A fluctuating photoperiod seems to have a dominating influence on the reproductive cycle.
Impending egg laying is preceded by an arrested appetite and excessive activity by the female. Gravid females will dig several test nests searching for an appropriate place to lay. It is important that a suitable nesting area is provided to the female. If not, she may retain the eggs longer than desired, which could cause low hatching success and/or health problems.
If the conditions are appropriate in the enclosure, eggs can be left where they were laid for incubation. If the nest chamber can be located, which can be difficult in large nesting areas, it is probably better to remove the eggs for artificial incubation. Rock iguana eggs are large and require adequate oxygen and humidity. Several incubation media, including sand, peat moss, vermiculite, or various mixtures of these, have been used with good success. A temperature of 30°C results in high hatching success and healthy, fertilized eggs will hatch in 80 to 100 days.
Care of neonates should be similar to that of adults, although extra precautions should be taken to ensure adequate hydration. With enough space, juveniles can be raised together. Some species may show more conspecific aggression than others, and this needs to be watched closely to ensure that severe problems do not arise. Diet can be similar to that of the adults. More animal protein is preferred by some species, whereas others may virtually ignore insects. Well cared for hatchlings can grow quickly and require substantial space to mature adequately.
Eggs of the Lesser Caymans iguana.
