The Island of Fernandina and the Marine Iguana

Occasionally, instead of visiting life on the islands,  some of the inhabitants come to us. This frigate bird has stopped by to supervise us as we prepare to go to Fernandina.

frigate bird supervisor

After lunch we visit Fernandina, the third largest of the Galápagos Islands. It is also the youngest and most active, rising right above the hot spot.

The kind of volcano that continues to build Fernandina produces lava so hot that it flows easily, forming a shield shape.  Fernandina’s caldera -- the crater created when the mouth of the volcano collapses -- is about 4500 feet high. While the island has periods of relative calm, it is still very active with eruption reported in June 2018. 

 Map of Fernandina from mappery.com

We are going to a visitor site at Punta Espinosa, not far from Isabela’s  Tagus Cove.
The flat lava of Punta Espinosa has a Hawaiian name-- Pahoehoe-- that describes this barren, puffy/rippled lava surface.

Pahoehoe lava of Punta Espinosa on Fernandina

This does not look like it would welcome life.  Yet Punta Espinosa has one of the largest concentrations of marine iguanas,  and also is home to flightless cormorants, Galapagos penguins, and sea lions.

I’ve mentioned the Galapagos marine iguanas are the only sea-going lizards in the world; the different islands each have their own subspecies of iguana. The largest are on Fernandina and Isabela.

Meet Fernandina’s marine Iguanas.

Like most lizards,  the iguana bodies do not effectively retain warmth, so in the daytime they sit in the sun and absorb its heat, huddling together to better retain it.

The marine iguana diet consists of algae that thrives on the sea’s underwater rocks. When they're warm enough (and hungry enough), the iguanas take to the ocean.  Long sharp claws enable them to cling to the rocks as their sharp teeth scrape off the algae. When underwater, their heartbeats slow down to help them conserve energy and feed for as long as possible.  Generally stay submerged for ten to fifteen minutes, but they larger ones can stay underwater for close to an hour.

Dining on sea algae means a very high-salt diet.  Iguanas have glands that help filter their blood of excess salt, which they expel by sneezing. This forms salt crystals on their snouts.

You remember Sally Lightfoot, the agile crabs we saw on the rocks? 

Sally Lightfoot crab- the iguana groomer

The crabs' main diet consists of the dead algae and parasites they get by grooming the iguanas.  A nicely balanced level of cooperation that keeps both creatures happy.

I couldn't resist .....

 If you'd like to see a marine iguana

Sea Galapagos beach life in action: if the video below doesn't work, please visit 
https://youtu.be/4MXUcoLEwS4.

 

Next:   Sea Lions

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