The marine iguana is one of the Galápagos Islands’ most famous residents, an evolutionary oddity found nowhere else on Earth.
Interesting facts
- Large males can dive to over 10 m to graze algae.
- They bask on black lava to warm up after cold dives.
- During El Niño events, when algae die off, marine iguanas can actually shrink in length.
- Colours vary by island; on Española breeding males turn red and green.
- Darwin described them as ‘imps of darkness’.
- There are several subspecies on different islands.
Behaviour
Iguanas gather in large groups on rocks, feeding at low tide or by diving, then basking for hours to recover body heat.
Breeding and young
Females dig nests in sand and lay one to six eggs; males defend small territories during the breeding season.
Threats and conservation
El Niño events that reduce algae, introduced predators such as cats, dogs and rats, oil spills and climate change.
Where to see it
- Fernandina Island
- Española Island (colourful subspecies)
- Santa Cruz and Isabela, Galápagos
Status source: IUCN Red List. Profile last reviewed September 2026.
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