In Cold Blood: Galapagos Marine Iguanas

I vividly remember the first marine iguana we spotted in the Galapagos. We were on Santa Cruz Island, walking on the beach at Tortuga Bay.  He was a huge male sitting alone on an exposed lava rock above the beach.  Of the many amazing creatures I’d come so far to see, this one ranked probably just behind the Galapagos giant tortoises in terms of how excited I was to see them up close.


We spent probably 20 minutes sitting on this rock photographing this lone iguana from every conceivable angle until we finally followed him as he ventured out to sea for a meal.   (Also on the same rock, we spotted our first bright red, Sally Lightfoot Crabs, and this Galapagos reef octopus.)

Tracks of the Galapagos marine iguanas

We took careful note of the trail he had blazed in the sand, and upon continuing our walk along the beach, we immediately noticed many more trails just like it, and we knew he was not alone.  Of course, about 100 meters down the beach, we found hundreds more, some warming themselves in the sun, others relaxing in the shade.  And like we would find with most animals living on the islands, none of the iguanas paid any attention to us as we walked by.

The Only Marine Iguanas on Earth

Perhaps the most rewarding aspects of a visit to the Galapagos are the many experiences you can have there and nowhere else.   By appearance, the marine iguanas don’t differ much from their land cousins also living on the islands – they can even interbreed, still.  Scientists believe the two subspecies evolved from a single ancestor after arriving on the islands.  But these are only ones that swim.


Most subspecies found in the Galapagos are black, but on Floreana and Espanola Islands, you can find brightly colored red and green iguanas. We saw the one above on Floreana Island.

Snorkeling Allows You To See Them Feeding Up Close

Marine iguanas swim not with webbed feet, but rather with a full body motion using their tail to propel through the water.  They dive to the bottom in order to feed on algae and seaweed.  While snorkeling, you can stay on the surface to watch them swim by, or you can swim out a little further and try to dive down to find them feeding on the algae-covered rocks below.

Galapagos Marine Iguana Underwater

The Infrared Camera Tells Us Even More

If you’re walking along the lava beds on a guided tour, you might see hundreds of iguanas lounging around on the black rocks and assume life is pretty easy for them.  Wouldn’t we all like to lie motionless while basking in the warm, equatorial sun?

Hundreds of Galapagos marine iguanas

But as cold blooded animals, what could easily be mistaken for laziness is actually a fairly desperate struggle to maintain body heat, conserve energy, and finally eat just enough food along the ocean floor in order to survive.

Due to currents that swell up from the ocean depths and originate all the way in Antarctica, the water surrounding these islands for half the year is very cold.  However, since cold water can dissolve more carbon dioxide to support photosynthesis, these currents are the driving force of life in the Galapagos.  The larger males can dive deeper and longer before their body temperatures cool and they must return to land or perish.

In David Attenborough’s Life In Cold Blood series, he used an infrared camera that gives a fascinating picture of how the Galapagos marine iguanas truly lives.  For me, even though I vaguely understood how the iguanas regulate heat in their bodies, seeing the video below brought that concept into crystal clear focus.  Attenborough has completely changed the way I view these amazing creatures:

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  1. Wow, those creatures are something!
    suki recently posted…Sunday Swig #21 – SF Beer Week is longer than a week!My Profile

    • Cassie Kifer says:

      They are especially intimidating-looking underwater, and surprisingly quick swimmers so when I first saw one while snorkeling I was a bit freaked out!

  2. Wow, amazing photos! So nice to take a closer look at these creatures.
    Pola ( recently posted…San Francisco Ferry Building and Marketplace: Gourmet centralMy Profile

  3. I prefer Belize’s green iguanas! 😉
    Lorenzo recently posted…Would You Like A Panty Ripper???My Profile

    • Kevin Adams says:

      I will have to visit Belize and decide for myself! These guys are a tough act to top, though. But I love discovering wildlife anytime, anywhere!

  4. I think I prefer seeing them in your lovely photos, or from a distance. I would probably freak out mightily if I encountered one underwater!
    Steph recently posted…Foto Friday: Randy’s DonutsMy Profile

    • Kevin Adams says:

      Nah, they are very calm animals. Charles Darwin called them “Imps of Darkness,” but he might have been a bit dramatic there. They hardly move at all on land, and in the water, they are focused on getting in, eating as much as they can, and then getting out to warm up on the rocks again. It really is a matter of life and death for them, so they don’t have the time to bother you if you’re swimming near them.

      • That’s good to know, but odds are that such knowledge probably wouldn’t prevent me from freaking out. “Imps of Darkness” are badass, though. If I ever start a band I might have to name it Imps of Darkness. Oh heck, why not go OTT and call it Darwin’s Badass Imps of Darkness. That name as “ukulele” written all over it 😉

        • Cassie Kifer says:

          Yes, it does! Your first album should be called “Booby”, and your second should be called “Los Pingüinos”

          • Haha. Los Pinguinos is epic. You would have laughed your ass off at my feeble attempts to say “Do you have a shirt that says “I love penguins’?” in Spanish. Wanted to see if I could find a t-shirt similar to what my robot self wears and I reckoned Chile would be the place to shop for such a garment. Not so much.
            Steph recently posted…Foto Friday: Ascending CorcovadoMy Profile

          • Cassie Kifer says:

            I had a hell of a time finding a yerba mate gourd in Chile, something that I thought would be easy, considering everywhere I looked, people were drinking out of them! So I believe it! :)

        • Kevin Adams says:

          It’s definitely a better band name than “Fun,” that’s for sure. “Fun” is just terrible. Gosh I am getting old fast. :(

          • Cassie Kifer says:

            There was a band named “Fun?” Yes. You are old. :)

          • Yes Kevin, you’re starting to sound a bit curmudgeonly. Cassie, thank you for momentarily making me feel like I’m up on popular culture. Usually I’m completely out of touch, but I do know that Fun won the Grammy for Song of the Year. Right, I must stop steering this convo off the topic of iguanas.
            Steph recently posted…Foto Friday: Ascending CorcovadoMy Profile

          • Cassie Kifer says:

            I love the irony in this… oops! Googling “Grammy 2013 Fun” right now to try to figure out who the heck they are!

  5. Iguanas are awesome. I was just looking at my videos from the Galapagos and I caught some ‘spitting’ salt water out of their noses….can’t wait to post it!
    Red Hunt recently posted…Hammock HappinessMy Profile

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