Galapagos Marine Iguana
Charles Darwin Evolution Theory and Big Idea Exhibition in London
Dec 8, 2008
Marine Iguanas swim well and have anatomical and physiological adaptations that suit them well to their harsh environment.
Marine Iguanas
- The Galapagos Marine Iguana (Amblyrhynchus cristatus) is the only living marine lizard, and one of the few marine reptiles that still exist.
- They live on the coast and dive regularly to get at their seaweed food. This cools them down, so they need to return to the rocks every half hour or so to bask in the sunshine. Before they warm up they get very ‘grumpy’ – attacking rather than running away from trespassers.
- Their diet is naturally very salty, and they have evolved a mechanism where they snort out excess salt. (Watch a short YouTube video of a Marine Iguana blowing out salt ). This can cover their face and head with a powdery white ‘mask’, not exactly adding to their beauty!
El Ninio seasons reduce the availability of their food, and there is evidence that they have adapted by being able to shrink a bit when times are hard. They do not simply get thinner – their skeletons actually become smaller.
Charles Darwin and Galapagos Wildlife
- Darwin wrote that: ‘the black Lava rocks on the beach are frequented by large most disgusting clumsy Lizards. They are as black as the porous rocks over which they crawl … I call them 'imps of darkness'.’ He was clearly not enamoured of the beasts, and – contrary to popular belief – he was not particularly impressed by ‘Darwin’s Finches’ during his visit to the Galapagos Islands.
- It was the mockingbirds that he caught there in 1835 that actually set him thinking about how animals might change and then evolve into new creatures. He wrote that 'Such facts (that two varieties of the same species of mockingbird could exist on two different islands) undermine the stability of species'.
The Darwin exhibition (‘Big Idea Big Exhibition’) at the Natural History Museum in London has been organised in collaboration with the American Museum of Natural History, the Museum of Science in Boston, the Field Museum in Chicago and the Royal Ontario Museum in Toronto, Canada. It runs until 19 April 2009.
The first two things that a visitor sees on entering the room are:
- A reconstruction of a Galapagos rocky shore covered with stuffed Marine Iguanas, and
- The two actual mockingbirds that Darwin collected back in 1835.
This is actually the start of a sort of ‘Darwin Season’. Next year (in September 2009) a new ‘Darwin Centre’ opens next to the Natural History Museum in London. According to the Director (Dr Michael Dixon) ‘it will show the public more of our vital research and our internationally important collections. I hope the centre will inspire people to think about the natural environment differently and in turn inspire them to take better care of our planet.' Darwin would have been proud!
References: The Natural History Museum and Dr.Robert Rothman’s webite.
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