Exploring Reptiles: Marine Iguanas

printable marine iguanas fact sheet

Marine Iguanas                       

Where Do They Live?
Marine iguanas are native to the Galapagos Islands where they live in colonies on rocky shores.

What Do They Eat?
Marine iguanas are herbivores.  They eat algae and seaweed that
grow on the rocks along the coasts of the islands.  They usually spend about 10 minutes underwater scraping the algae off of the rocks, but can spend up to 30 minutes under water feeding.

Do They Have Adaptations?
Marine iguanas have adapted to survive in their habitat.  They have short, rounded snouts and razor sharp teeth that make it easy to scrape algae off of the rocks.  Flattened tails make marine iguanas excellent swimmers and sharp claws grip rocks easily.  The dark color of their skin helps absorb heat.  Special glands near the nostrils help marine iguanas “sneeze” out the salt from the water they ingest.  The expelled salt clings to their snouts, and looks like a beard or wig.

Do They Have Natural Enemies?                                                 
Animals that were introduced to the Galapagos by
explorers and traders prey on marine iguanas.
These animals – dogs, cats, rats, and pigs – prey
on adult iguanas as well as their eggs.



Did You Know…

  • Marine iguanas are the only reptile on earth that spends time in the sea.
  • Marine iguanas likely evolved 8 million years ago as a result of land iguanas drifting out to
    sea from South America, landing on the Galapagos Islands.
  • The Galapagos Islands are a volcanic archipelago (chain of islands) on the coast of Ecuador.
  • Marine iguanas are a protected species. The IUCN (International Union for Conservation of Nature) considers the marine iguana vulnerable.  Rise in sea level, oil spills,  and warming air temperatures affect nesting sites and the development of eggs.
  • Marine iguanas live in large colonies of about 1,000 individuals. In a one mile area there can
    be up to 4,500 marine iguanas living together.
  • Marine iguanas can be up to 4 feet long and weigh up to 3 pounds.
  • Each of the Galapagos islands has marine iguanas of different sizes and coloration.
  • Marine iguanas have long spines on their backs running form neck to tail, thick bodies and legs, and bony plates on the head.
  • When food in in short supply the marine iguana can lose up to 20 percent of its body weight and shrink its skeleton, a change scientists still can’t explain.

Charles Darwin described  marine iguanas as “hideous-looking” and “most disgusting, clumsy lizards”.

What do you think?

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