The Galapagos Islands are home to one of the most remarkable reptiles on Earth: the yellow iguana (Conolophus subcristatus). With an impressive lifespan of up to 70 years in the wild, these large lizards manage to survive in some of the world's harshest environments. As we continue to learn more about these amazing creatures, it becomes clear that we must intensify our efforts. At Galápagos Conservancy, we are committed to protecting this extraordinary species to ensure its survival. The story of the yellow iguana is a powerful example of the species' own resilience, and a call to action to protect this extraordinary treasure.
Population and distribution
Understanding where and how many yellow iguanas still living are essential for effective conservation. Detailed information about population sizes, habitats, movement patterns, and connections between populations helps us develop more effective management strategies. Identifying specific threats to each population also allows us to focus our conservation efforts where they are needed most.
The yellow iguana is one of three species of land iguanas in the Galapagos Islands that are found nowhere else on Earth. The other two species are the pink iguana (C. marthae), found only at Wolfe Volcano on Isabela Island, and the pallid iguana (C. pallidus). Yellow iguanas live on the islands of Isabela, Baltra, Fernandina, South Plaza, Santa Cruz and Santiago. Land iguana populations have declined throughout their range due to habitat destruction by introduced herbivores, mainly goats, and predation by introduced carnivores, mainly feral dogs and cats, but still thrive in a few places, such as South Plaza Island and North Seymour Island. where they were introduced from Baltra Island almost 90 years ago.
Reintroduction and conservation successes
On Santiago Island, the land iguana was extirpated by the mid-19th century, and the last observation was recorded by Charles Darwin during his visit in 1835. Extirpation of the species was mainly due to invasive species such as feral pigs, which were not eradicated until 2001. Since 2019, 3,143 iguanas have been slowly reintroduced from North Seymour Island back to Santiago Island to re-establish the species there and serve as an ecosystem engineer to aid the island's recovery.
Baltra Island has historically had a thriving population yellow land iguanas, known to be the largest of all species. However, this population declined in the early 20th century due to habitat destruction caused by introduced feral goats. The situation worsened during World War II due to the construction of a large US military base on Balta, which led to the complete disappearance of iguanas from the island.
Between 1932 and 1933, before the iguana population on Baltra disappeared, seventy iguanas were transported to North Seymour, just half a mile away. This transfer was orchestrated by American tycoon William Randolph Hearst, who, seeing the decline in iguana numbers and vegetation due to goats on Baltra, decided to relocate them as an experiment. This move helped prevent the Baltra iguana from becoming extinct.
In the early 1980s, the North Seymour iguanas were used to begin a breeding program in 1991 with the goal of repopulating Baltra. The program has been successful: today there are approximately 3,000 iguanas living on Baltra.
Diet and adaptations
Galapagos land iguanas are primarily herbivores, feeding on green grass where it is available. as well as leaves, flowers and fruits of herbaceous plants and small shrubs. They are also known to eat invertebrates such as millipedes, spiders and even carrion. Because the islands have limited fresh water, land iguanas obtain most of their hydration by eating prickly pear cactus and other succulent plants.
Source: galapagos.org
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