Galapagos Land Iguanas
There are two species of land iguana found in the Galapagos Islands - Conolophus subcristatus is native to six islands, and Conolophus pallidus is found only on the island of Santa Fe. They are large (over 1 metre long), yellowish animals, with males weighing up to 13 kilograms. Galapagos iguanas are thought to have had a common ancestor which floated out to the islands from the South American mainland on rafts of vegetation.
They live in the drier areas of the islands and in the mornings are found sprawled beneath the hot equatorial sun. However, to escape the heat of the midday sun, they seek the shade of cactus, rocks, trees or other vegetation. At night they sleep in burrows dug in the ground, to conserve their body heat. The land iguanas show a fascinating interaction with Darwin's finches, raising themselves off the ground and allowing the little birds to remove ticks.
Land iguanas feed mainly on low-growing plants and shrubs, such as the cactus, as well as fallen fruits and cactus pads. These succulent plants provide them with the moisture they require during long, dry periods.
Land iguanas reach maturity between 8 and 15 years of age. Males are territorial and will aggressively defend specific areas, that typically include more than one female. Following the mating period, the female iguanas migrate to suitable areas to nest, and will lay between 2 and 25 eggs in a burrow dug in the sandy soil. The female defends the burrow for a short time, to prevent other females from nesting in the same place. The young iguanas hatch 3-4 months later, and take about a week to dig their way out of the nest. If they survive the first difficult years of life, when food is often scarce and predators are a danger, land iguanas can live for more than 50 years.
In 1976, wild dogs wiped out a colony of almost 500 land iguanas at Conway Bay on Santa Cruz. Together, the CDRS and GNPS launched an emergency rescue operation for the 60 or so survivors. Shortly thereafter, another large-scale attack occurred at Cartago Bay on Isabela, and 30 more iguanas were rescued. To help re-establish the land iguana populations, the GNPS and the CDRS began a breeding and rearing programme for iguanas. They established a breeding centre in Santa Cruz, to increase the populations that were seriously threatened by feral animals. Twelve years later repatriation started and it continues today. The CDRS and the GNPS carry out regular monitoring of this population.
The captive breeding programme is reinforced by an ongoing campaign for the eradication and control of introduced species throughout the islands. The populations of wild dogs were eliminated from Cartago and Conway Bays, and goats were removed from several small islands, while pigs and wild cats are now controlled in critical areas on others.
Future goals for the Iguana Breeding Centre
The CDRS and the GNPS have had incredible successes with this programme, but there is still much more to be accomplished in order to protect the land iguana populations and conserve the ecosystems of Galapagos. The main goals to be reached at the Iguana Breeding Centre include:
- Maintain the habitat for the iguanas in optimum conditions
- Incubate iguana eggs from Santa Cruz and Baltra
- Look after adult iguanas amd juveniles that are kept in captivity
- Maintain the installations of the breeding centre
It is also essential to continue monitoring the iguanas and controlling/eradicating the introduced species that are a threat to the survival of land iguanas throughout Galapagos.