🦎 Marine Iguanas: Ocean-Swimming Lizards of the Galápagos

Marine iguanas are one of the most unusual reptiles in the world. They are the only lizards that live and feed in the ocean, and they exist nowhere else but the Galápagos Islands. These cold-blooded swimmers dive into the sea to graze on algae, then warm up by basking in the sun on lava rocks.

They may look like little dragons, but marine iguanas are peaceful plant-eaters who play an important role in their coastal ecosystem—and they face serious threats from climate change and human activity.

🌍 Habitat and Range

Marine iguanas live only in the Galápagos Islands, a volcanic archipelago in the Pacific Ocean, about 600 miles off the coast of Ecuador.

They live along the rocky shores of the islands and can be seen:

• Sunbathing on black lava rocks
• Swimming through shallow coastal waters
• Crawling along beaches and mangroves

There are different subspecies of marine iguanas on each island, with some variations in size and color.

🧬 Body Features and Adaptations

Marine iguanas have several special adaptations for their unusual marine lifestyle:

• Flattened tails – used like paddles for swimming
• Strong claws – help them grip rocks in crashing waves
• Salt glands – remove salt from their blood and sneeze it out through their noses
• Dark skin – absorbs heat quickly after cold ocean dives
• Blunt snouts and sharp teeth – perfect for scraping algae off rocks

Most marine iguanas grow to about 1 to 4 feet long, but males are much larger than females. The largest subspecies lives on Isabela Island and can weigh up to 11 pounds (5 kg).

🌿 Diet and Feeding Behavior

Marine iguanas are herbivores, meaning they eat only plants. Their main food is:

• Algae and seaweed that grow on underwater rocks

Feeding habits:

• Males often dive into the ocean to graze on deep-sea algae
• Females and smaller iguanas feed in the intertidal zone during low tide
• Dives can last up to 30 minutes, but most are much shorter

They have flat teeth that work like a comb to scrape food, and they often return to the same feeding spots.

☀️ Thermoregulation (Warming Up)

Because marine iguanas are cold-blooded reptiles, they rely on the sun to warm their bodies after swimming in chilly water.

You’ll often see them:

• Basking in the sun in big groups
• Flattening their bodies to soak up heat
• Sitting very still to save energy

If they get too cold, they become slow and clumsy—making it harder to escape predators.

🐣 Life Cycle and Reproduction

Marine iguanas breed once a year. Their life cycle includes:

• Males fighting for territory during the mating season
• Females laying 1–6 eggs in burrows in the sand or soil
• Eggs incubating for 2–4 months before hatching

Young iguanas face danger from:

• Hawks, snakes, rats, cats, and other introduced predators
• Cold temperatures and rough conditions

Those that survive may live up to 60 years, though most don’t live that long in the wild.

⚠️ Threats and Conservation

Marine iguanas are listed as vulnerable, and some subspecies are endangered.

🚨 Main threats include:

• Invasive species (like rats and cats) that eat eggs and hatchlings
• Climate change – warming oceans reduce algae growth
• Oil spills and pollution – harm their habitat and health
• Tourism and habitat disruption

🛡️ Conservation efforts:

• Galápagos National Park protections
• Control and removal of invasive predators
• Marine reserves around key feeding areas
• Scientific monitoring and population studies
• Public education to promote responsible tourism

Marine iguanas are protected by Ecuadorian law, but continued effort is needed to preserve their future.

🎉 Fun Facts About Marine Iguanas

• They are the only marine lizards in the world
• They sneeze salt to stay balanced after drinking seawater
• Charles Darwin called them “disgusting, clumsy lizards”—but he was fascinated by them
• They can shrink in size during times of food shortage
• Males can turn bright red and green during mating season (nicknamed “Christmas iguanas”)

🧠 Vocabulary List

• Herbivore – An animal that eats only plants
• Endemic – Found only in one place in the world
• Thermoregulation – The ability to control body temperature
• Intertidal zone – The area of shore that is underwater at high tide and dry at low tide
• Adaptation – A special feature that helps an animal survive
• Subspecies – A group within a species with unique traits
• Salt gland – An organ that removes excess salt from the body
• Ecosystem – A community of living things and their environment
• Invasive species – Animals introduced to a place where they don’t belong
• Vulnerable – At risk of becoming endangered

✅ Marine Iguana Quiz: Can You Spot the Sneezing Lizard?

1. Where do marine iguanas live?
A. Hawaii
B. Australia
C. The Galápagos Islands
D. Florida
✅ Answer: C. The Galápagos Islands

2. What do marine iguanas eat?
A. Fish
B. Crabs
C. Seaweed and algae
D. Insects
✅ Answer: C. Seaweed and algae

3. How do marine iguanas remove salt from their bodies?
A. Through sweat
B. Through their shell
C. By sneezing it out
D. Through their tails
✅ Answer: C. By sneezing it out

4. What helps them swim in the ocean?
A. Webbed feet
B. Flattened tails and strong claws
C. Fins
D. Wings
✅ Answer: B. Flattened tails and strong claws

5. Why are marine iguanas in danger?
A. They are hunted for meat
B. They fight too much
C. Invasive species and climate change
D. They are bad swimmers
✅ Answer: C. Invasive species and climate change

🧒 Kid-Friendly Summary

Marine iguanas are one-of-a-kind ocean lizards that live only in the Galápagos Islands. They swim in the sea to eat algae, then warm up on sunny rocks. They sneeze out salt, hold their breath while diving, and even change color in mating season.

But these cool creatures need our help—climate change and predators are putting them at risk. Protecting marine iguanas helps keep the whole island ecosystem healthy.