What I Learned about the Incredible Downsizing Marine Iguana

My favorite fun fact of the week came from browsing the National Geographic feed on Instagram. I came across a picture of a marine iguana–not the most striking image I’ve ever seen on the National Geographic feed–but the description beneath the image really caught my attention.

The marine iguana can shrink. I don’t mean it dehydrates itself, or loses fat. I mean it reduces the size of its skeleton! It can lose up to 20% of its size!

Why would the marine iguana evolve to do that?

Biologists believe it’s an adaptation to help the iguanas survive in times when food becomes dangerously hard to find. Instead of starving to death, marine iguanas downsize. As smaller predators, they require less food to stay alive.

Doing a little more research, I learned that not only can iguanas shrink, but they can grow again when food becomes more plentiful. You can check out the article on Gizmodo here.

Evolution is all about stayin’ alive (cue the Bee Gees here). What a fascinating way to survive in times of scarcity.

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