The marine iguana (Amblyrhynchus cristatus) is one of the most extraordinary animals of Galápagos. Endemic to the archipelago, it is the only living lizard on Earth that regularly feeds in the sea. It inhabits the coasts of all the main islands and many islets, where lava, tides, and cold ocean currents have shaped a truly unique anatomy.
Its short snout allows it to scrape algae from rocks, while its strong claws keep it firmly attached against the surf. Its laterally flattened tail works as a powerful fin when swimming. Because it feeds in salt water, it takes in large amounts of salt, which it expels through glands connected to its nostrils. That is why it is often seen “sneezing” small jets of salt.
As a reptile, it depends on external heat to regulate its body temperature. After swimming in the cold waters of Galápagos, it returns to land and stretches out on volcanic rock to absorb the sun’s warmth. This constant alternation between ocean and lava defines much of its life.
Marine iguanas vary in size and color from one island to another, the result of a long history of isolation and adaptation. During the breeding season, some males develop especially intense reddish, green, or turquoise tones.
The species is classified as Vulnerable. Events such as El Niño can drastically reduce the algae on which it depends and cause severe population declines. Few species capture the essence of Galápagos as clearly as the marine iguana: visible evolution, extreme survival, and an inseparable connection between land and sea.
