In reality, these harmless lizards are alive today, but endangered in their own native land. However, when whalers and settlers started visiting the islands in the early 1800's, it is likely that humans found land iguanas as tasty as the tortoises and caused damage to some populations. Later the domestic animals they brought caused huge problems for the endemic land iguanas.
Cats hunt the young iguanas and dogs kill adults.
Today, the abundant iguanas that Darwin wrote about on Santiago Island are extinct. On some other islands, the populations are severely diminished. In 1976, wild dogs wiped out the last remaining colonies of land iguanas from Cerro Dragon to Conway Bay on Santa Cruz. Shortly, thereafter, it was discovered that the same destructions was happening on Southern Isabela. To help reestablish Land Iguana populations, the GNPS and the CDRS began work on a program for iguanas, establishing a breeding Center in Santa Cruz, to recover the populations.