Did you know that some creatures have blue blood?

And not because they’re super fancy, either. 🙂

I originally looked into copper because it’s one of the oldest recognized elements. There’s evidence of human use of copper dating back to at least 4500 BCE, and archaeologists are learning more about it all the time. Retracing the original methods of smelting copper was a major passion of one of my professors in grad school! And because I spent many of my precious university hours grinding up malachite (a rock in which copper is found), I already knew something about copper which most people don’t: even though the metal we know of as copper is a reddish-gold, oxidized copper can be green or blue.

And that brings us back to the main point of the day! In the same way we have iron in our blood that gives it its red hue, some creatures have copper in theirs. That gives their blood a blue tinge — and it also helps them survive in very cold or iron-lacking environments. Say, the bottom of the ocean?

Octopuses and squids both have blue blood, as do some other sea creatures. So, apparently, do spiders and scorpions . . . not sure I want to investigate that, though. 🙂

Selected Resources

Dingle, Adrian, and Dan Green. The Complete Periodic Table. Basher Science. Kingfisher, NY: 2015. (This book is aimed at a younger audience but is a great source of succinct, fun information!)

Staughton, John. “Why do Squids and Octpuses Have Blue Blood?” Science ABC, here.

Storgaard, Morten. “17 Animals With Colorful Blood.” Animal How, here.