Meet the only lizard that lives half its life in the ocean

A closer look at this seafaring reptile

The marine iguana doesn’t just paddle around for fun—it dives into the ocean to feed on algae and seaweed that grow on underwater rocks. They can hold their breath for up to 30 minutes, although most of their dives are short, around 5–10 minutes.

They aren’t flashy swimmers, but they’ve got strong, flat tails—like a crocodile’s—that help them move easily. Their long claws are perfect for hanging onto rocks when the waves crash.

But after a swim, they get cold. Being cold-blooded means they rely on the sun to warm up. So you’ll often see them lying flat on the volcanic rocks, soaking up heat like a solar panel.

Though they may seem slow and sluggish, especially when sunbathing, they can move fast if threatened (Source: Wikimedia Commons)

Living in the ocean means swallowing a lot of saltwater, and that’s not ideal. These iguanas have a clever trick: they sneeze out the salt through special glands near their noses. It’s not the most glamorous skill, but it keeps their bodies balanced.

They also have dark, scaly skin that heats up quickly, helping them recover from the ocean’s chill. During breeding season, males get colourful—sometimes turning red and green—to impress the females.

Marine iguanas don’t live fancy lives. They huddle together for warmth, especially at night, and lay their eggs in sandy burrows on land. The babies hatch weeks later and must learn quickly to survive—hawks and snakes are always watching.

Though they may seem slow and sluggish, especially when sunbathing, they can move fast if threatened. They aren’t aggressive but will puff up and bob their heads to warn others.

Why they need our help

Sadly, marine iguanas are vulnerable to extinction. Rising ocean temperatures, oil spills, and invasive animals like rats and cats threaten their eggs and food supply. Even something as simple as plastic waste can harm them.

Efforts are underway in the Galápagos to protect their nesting sites and keep their ecosystems clean. Scientists regularly monitor the populations, and local conservation groups are working hard to control invasive species and educate visitors.

When Charles Darwin visited the Galápagos in the 1830s, he called them “imps of darkness.” But over time, people have grown to admire their strange beauty. These ancient reptiles are living links to a time when dinosaurs ruled the world.

And while most of us may never see one in person, the marine iguana reminds us of how life can adapt in the most surprising ways.