Land iguanas once thrived on Santiago—one of 19 small volcanic islands that make up the Galápagos archipelago (see Where in the World: Galápagos). When the famed naturalist Charles Darwin visited Santiago in 1835, the island was crawling with the 1 meter (3 foot)-long lizards. There were so many, in fact, that Darwin had trouble finding a clear patch of ground on which to pitch his tent. Soon after Darwin’s visit, though, the iguanas on Santiago disappeared. Today, fewer than 10,000 of the animals remain, scattered on other islands in the Galápagos.
Workers with Galápagos National Park, along with scientists like Castaño, have relocated more than 2,000 iguanas from other parts of the Galápagos to Santiago. It is the largest iguana repopulation effort in history. And it’s a big step toward restoring the biodiversity, or variety of life, that the Galápagos had before humans first arrived.