THE UNIQUE MARINE IGUANAS

      Marine iguanas are unique, three-foot-long lizards endemic to the Galapagos Islands.  They have a few characteristics that make them interesting.  They are the only lizards on Earth to ingest algae from rocks on the bottom of shallow Pacific Ocean waters, just off the lava-strewn edges of the Galapagos.  They can stay underwater for up to 30 minutes, while grazing on algae, as sheep do in meadows.  Since they take in much salt water while ingesting algae in the ocean, they have special salt-expelling glands near their nostrils that "sneeze" out excess salt.  And they can slow their heart rates to avoid detection by nearby, predatory sharks.  Many aspects of nature are beyond belief.

     Marine iguanas are cold-blooded, as all reptiles are.  And they are as dark as the lava rocks they congregate on to rest and soak up warming sunlight between feeding forays in the ocean.  Their coloration camouflages them against hawks while resting on the lava. 

     When sufficiently warm, these iguanas have the energy to dive underwater and swim to the bottom to scrape algae off the rocks with their mouths until they are full.  Then they swim to the surface and clamber onto the lava rocks bordering the ocean to bask in sunlight to warm up again.

     While those groups of marine iguanas rest together on rocks, tiny lava lizards move about and on them to catch and ingest flies that hover around the iguanas.  Lava lizards also eat the dead skin off the iguanas' backs as a handy, abundant food supplement.  On volcanic islands, creatures must adapt to eating whatever is available to them, including the iguanas eating underwater algae and lava lizards consuming the dead skin on the iguanas.    

     Female iguanas lay eggs in sand back from the ocean shorelines.  Sunlight warms the sand, which warms the embryos in their eggs and allows them to develop.  After two months, the young iguanas hatch, emerge from the sand and make their way to their elders gathered on lava rocks by the ocean shore.  But racer snakes rundown some of the baby lizards, constrict them to death and consume them.  

     Marine iguanas probably got on the Galapagos Islands by riding on logs and driftwood floating in Pacific Ocean currents from the western shorelines of South America.  Because they are cold-blooded and need little food, they could survive such trips across the Pacific.  The only food those pioneer iguanas could find on the Galapagos was the algae they feed on to this day.  Luckily for them, they are adaptable and can make do with what food is available.  

     Marine iguanas are adaptable and interesting creatures that, by accident, found a new home for themselves, creating a new species there.  All life on Earth is adaptable to varying extents, which is why most every niche on Earth is filled by one species or another.                  

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