Uncovering the Mystery of the Sneezing Galápagos Iguana

On my recent trip to the Galápagos, I could hardly contain my joy at seeing some of the animals that, until then, I had only seen on TV. The marine iguanas were one of my favorites, blending in with the lava rocks, not giving a care in the world about the human activity around them. But I noticed them doing something interesting -- every few minutes, an iguana would let out a big old sneeze, spraying out water up to several feet.

But why are these lava-looking reptiles firing out snot rockets?

To start, it's interesting to note that the marine iguanas, Amblyrhynchus cristatus, are the only lizards in the world to adapt to a marine lifestyle, as they swim out into the ocean to forage on algae.

Due to this feeding behavior at sea, understandably the iguanas ingest not only algae, but also a lot of extra salt (mainly sodium chloride along with some potassium). In order to deal with this excess amount of salt, the marine iguanas have a unique solution. A book on iguana biology summed it up pretty nicely:

To cope with this high-salt diet, the marine iguana uses large cranial salt glands that excrete most of the sodium, potassium, and chloride ingested; forceful expulsion of the secreted fluid is the cause of the dramatic snorting and sneezing observed in these animals.

So it turns out that violent sneezing is actually a pretty clever evolutionary adaptation to dealing with what would otherwise be a fatal salt overload! Not only did we get to see the world's only marine lizards, but I got to learn something new by getting iguana snot sprayed on me.

Thanks to Destination Ecuador for hosting Jason Goldman and I during our trip throughout several of the Galápagos Islands. I cannot wait to return! I know the iguanas will be right where we left them, blasting out salt water through their schnozes.

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