Why Does An Octopus Have Three Hearts?
And evolution even saw fit to create a creature with no heart!
The eight-armed cephalopod that we call Octopus is a truly amazing animal, and rather weird too. Evolution has seen fit to equip it with a myriad of peculiar attributes. Chief among these are its three hearts. Good thing, because without the trio of pumps the octopus would be as docile as a rock.
The complex octopus cardiovascular system (hearts, arteries and veins) includes two types of hearts – a “systemic heart” and two “branchial hearts.” The systemic heart is the primary pump responsible for moving oxygenated blood around the entire body and is a more typical muscular organ. The two branchial hearts are auxiliary pumps located in the veins that receive deoxygenated blood and pump it to the gills for oxygenation.
The evolution of three hearts is likely due to the chemical composition of their blood which, by the way, is blue! The blood of humans and other vertebrates includes an iron-based oxygen carrier (haemoglobin) that gives it its distinctive red color. However, the octopus has evolved with a copper-based oxygen carrier called haemocyanin, and it is this protein that makes its blood blue.
Unfortunately, haemocyanin is pretty lousy at carrying oxygen, and compounding the issue is that…
