Marine Iguana Facts | Galapagos Islands Wildlife Guide
These large, harmless creatures were called “hideous” by Charles Darwin, as they are probably among the most grotesque-looking reptiles. However, they were an important species in helping Darwin form his theory of evolution by natural selection.
- Males are 4.5 feet in length and can weigh a little more than 3 pounds
- Females can be almost 3 feet and weigh about 1 pound
- Skin is blackish, which can change to coppery greens and reds in males during breeding season. The males on Española Island are colorful year-round
- A row of spines covers the entire length of their backs
- Blunt noses help them graze on seaweed
- Flat tails help them swim
Range and Habitat
Marine iguanas are the only seagoing lizards in the world, and they are found on the rocky shores of most of the Galapagos Islands. In fact, they range only in the Galapagos. The absence of mammalian predators has helped them adapt well to a marine environment. Because the water surrounding the islands can be quite cold, and they are
Behavior and Communication
Marine iguanas are most active during the day, that is, after spending the first few hours of the day sunbathing and preparing for the day’s activities.
Marine iguanas are herbivores and feed mainly on intertidal seaweed and algae during low tide. When feeding, the larger iguanas, which can retain more body heat, may remain submerged in the water for up to one hour.
Iguanas tend to intake a large amount of sodium, which can be toxic to them. To accommodate this, they excrete salt crystals by sneezing a lot.
Breeding and Reproduction
Breeding occurs at different times on different islands, but
Mated females lay one to six eggs in a sandy nest or volcanic ash burrow that is 1,000 feet inland. Females guard the nest fiercely for several days but then leave the eggs while they finish incubating, which takes approximately 95 days. Hatchlings are not given any parental protection.
Marine iguanas are vulnerable, but since the creation of the Galapagos Marine Reserve in 1998, their status has somewhat improved. Their primary predators are birds, such as hawks, owls
Efforts made through the Charles Darwin Research Station to measure the iguanas’ corticosterone levels—basically, adrenaline—helps monitor the general health of the marine iguana population. Their stress increases
Header Credit: Roberto Plaza