Octopuses are among the most fascinating creatures in the ocean, and their unique biology sets them apart from almost all other animals. One of their most remarkable features is their cardiovascular system, which includes not one, but three hearts!
Two of these hearts are branchial hearts, located near each of the octopus’s two gills. These hearts pump blood through the gills, where it picks up oxygen. The third heart is the systemic heart, which pumps the oxygenated blood to the rest of the body.
Interestingly, when an octopus swims, the systemic heart actually stops beating, which is why octopuses prefer crawling over swimming. The branchial hearts continue working to keep blood flowing through the gills.
But that’s not the only unique thing about octopus blood. Unlike humans, who have iron-based hemoglobin that makes our blood red, octopuses have copper-based hemocyanin, which makes their blood blue! This copper-based protein is more efficient at transporting oxygen in cold, low-oxygen environments like the deep ocean.
This remarkable adaptation allows octopuses to thrive in environments where other animals would struggle, making them one of the ocean’s most successful predators.