Galapagos land iguana  (Conolophus subcristatus)

In the early 1800s, whalers and settlers came to the Galapagos Islands. It is likely that they ate land iguanas, but the most serious problem they caused resulted from the introduction, both accidental and deliberate, of predators such as cats and dogs and domestic animals such as goats and pigs (6). Introduced animals are still the main threat facing this species today (2). Cats and rats hunt eggs and young iguanas and introduced goats destroy food plants (4). The natural predators of land iguanas include hawks, herons, and snakes, all of which cannot prey on young after they reach around one year of age, as they become too large. However, cats can continue to kill young iguanas until they reach three or four years of age; cat predation is a huge problem preventing the natural success of the species (5).

In 1976, wild dogs wiped out the last colonies of land iguanas around Conway Bay on Santa Cruz Island. This prompted the Charles Darwin Research Station (CDRS) and the Galapagos National Park Service (GNPS) to initiate an emergency rescue scheme for the 60 remaining survivors. They then discovered that a similar level of destruction was occurring on Isabella Island. The GNPS and CDRS established a recovery programme, including a captive breeding scheme based on Santa Cruz. The captive breeding programme continues today, and land iguanas are returned to the wild when they reach a size beyond which they are safe from cat predation (2) (6). This breeding programme is accompanied by a campaign to work towards the eradication and tighter control of introduced animals. Other important measures include the maintenance of suitable habitat for the species, and continued monitoring of the populations (2).