An Iguana Species Last Documented by Charles Darwin Has Been Reintroduced to a Galápagos Island

The Galápagos land iguana on Santiago Island was decimated by invasive animals like cats, dogs and pigs

by Brigit Katz, January 9, 2019

During his journey to the Galápagos in 1835, Charles Darwin spotted land iguanas racing about on the island of Santiago. He wasn’t a fan. “From their low facial angle they have a singularly stupid appearance,” he wrote, also opining that the animals are “lazy and half torpid.”

Darwin, with his rather unforgiving assessment, was the last person to officially record a sighting of the reptiles on Santiago Island, nearly 200 years ago. The iguanas were decimated by foreign animals introduced by mariners and early settlers of the Galápagos. But there may be new hope for the iguanas of Santiago. As the Agence France-Presse reports, more than 1,400 land iguanas have been reintroduced to the island as part of a restoration program.

The Galápagos National Park authority explained on Facebook that the land iguanas, also known by their scientific name Conolophus subcristatus, had been relocated from the neighboring North Seymour Island, where the animals are far more plentiful; around 5,000 individuals lived there before part of the population was move to Santiago Island, according to the park. In fact, reducing land iguana numbers on North Seymour Island may prove beneficial since food resources, particularly cacti, are limited there.

The restoration initiative is taking place in a number of phases. Last year, land iguanas on North Seymour Island were captured and quarantined. On January 3rd and 4th of this year, they were released onto coastal regions of Santiago, which “have ecosystems similar to those of their natural habitat, with the presence of abundant vegetation for their food,” the park says. The team, which includes park officials and experts from New Zealand's Massey University, will begin monitoring the iguanas next month. CNN’s Emily Dixon reports that experts will be looking to see if the iguanas are building nests and getting enough food. They’ll also keep a close eye on species like rodents and ants, which pose a threat to the iguanas' nests.

In the past, Galápagos land iguana populations plummeted due to introduced animals like cats, dogs and rats, which competed with the animals for food and preyed on their eggs and young. But a major culprit in the reptiles’ decline has been pigs, which were brought to the island in the 1800s and have since run wild. Omnivorous and ravenous, feral pigs are “thought to have played a big role in many of the extinctions and ecosystem degradation on the Galápagos Islands,” according to the Galápagos Conservation Trust

Fortunately, the porcine predators won’t be pestering Santiago Island’s newest inhabitants. Pigs and other introduced mammals, like donkeys and goats, were eradicated there as part of a conservation project that took place between 1997 and 2006.

Galápagos land iguanas, a large species with powerful hind legs and yellow skin, are one of just three iguana species that are endemic to the Galápagos Islands. Danny Rueda, the park authority’s ecosystems director, notes that the land iguana “helps ecosystems through the dispersal of seeds and the maintenance of open spaces without vegetation.” In other words, Darwin’s opinions notwithstanding, the land iguana may play an important role in the ecological recovery of Santiago Island.

Reference: www.smithsonianmag.com