Octopuses have three hearts and blue blood; two hearts pump blood to the gills while the third pumps it to the rest of the body.
Sources
- https://medium.com/the-shortform/meet-the-octopus-the-creature-with-three-hearts-and-blue-blood-465ab3bdbf9e (medium.com)
- https://www.nhm.ac.uk/discover/octopuses-keep-surprising-us-here-are-eight-examples-how.html (nhm.ac.uk)
- https://www.msn.com/en-us/science/biology/octopuses-have-three-hearts-and-blue-copper-based-blood/ar-AA2a1tbD (msn.com)
- https://spacedaily.com/t-octopuses-have-three-hearts-and-blue-blood-that-carries-oxygen-using-a-copper-based-protein-rather-than-iron-and-because-the-heart-that-supplies-the-body-stops-beating-whenever-they-swim-many-bottom/ (spacedaily.com)
- https://wowtoknow.com/octopuses-have-three-hearts-and-blue-blood/ (wowtoknow.com)
- https://www.smithsonianmag.com/science-nature/ten-wild-facts-about-octopuses-they-have-three-hearts-big-brains-and-blue-blood-7625828/ (smithsonianmag.com)
- https://octonation.com/how-many-hearts-does-an-octopus-have/ (octonation.com)
- https://study.com/academy/lesson/the-octopus-circulatory-system.html (study.com)
- https://www.britannica.com/science/How-Many-Hearts-Does-an-Octopus-Have (britannica.com)