Wild Fact #984 – The Ultimate Diet – Marine Iguanas

Wild Fact #984 – The Ultimate Diet – Marine Iguanas


I have always had a fascination for the Galapagos Islands since this was the birth place of evolution.  Many animals that are capable to survive on those islands have adapted some unique characteristics to live in such a harsh environment.

Marine Iguanas are probably one of the most unique (in my opinion).  Not only are they capable of diving over 15 m (45′) to feed on algae but they can also change their size to adapt to their food requirements.  That’s right, if for some reason the food supply is reduced for a couple of years (i.e. algae growth is limited) then the marine iguana can shrink.  No, I am not just talking about the marine iguana losing weight because they joined Weight Watchers, their actual bones are able to decrease in size.  Impressive, eh! One study found that during the El Nino weather pattern the marine iguanas’ body decreased in size by almost 20%.  In a few years when the food returned so did their body size.  Just to relate this to humans, a drop in body size by 20% would be similar to a 6′ person shrinking to about 4′ 2″.  Imagine the implications to a pro basketball team during years of famine!

Did you enjoy this Wild Fact? Have you ever been to the Galapagos Islands? Do you have any pictures of the Galapagos?


  1. Avatar
    Bev Lawrence September 14, 2009

    Are these iguanas related to the iguanas the tourists get their pictures taken with down in Mexico? Possibly the ones in the pet store? I’ve never heard of this particular iguana.

    • Avatar
      Nathan September 14, 2009

      Good question!
      This particular iguana is a very unique animal that only exists on the Galapagos Islands. These islands have numerous volcanoes and little food. Thus the wildlife that survives on these islands have developed some incredible characteristics to be able to survive. It was these adaptations that lead Charles Darwin to the theory of evolution.

      It is possible that these marine iguanas are very distantly related to the land iguanas elsewhere in the world but they are not directly related. Some scientists believe that the marine iguanas are the last of its kind and has a completely separate evolutionary ancestor than the land iguanas.

      I am sure this is all as clear as mud!
      Thanks for the question!

  2. Avatar
    margo September 14, 2009

    Let’s go there!

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