Although the Galapagos Islands are a paradise for bird watchers, they are best known for their reptile population. The two species of iguana, the land and the marine iguana, are unique species found nowhere else in the world. While people sometimes think they look fearsome, both are vegetarians. The land iguana, which is yellow/brown in color, lives largely on cactus and has learned to scrape large thorns off the cactus pads with its feet.