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Octopi, octopuses, and octopodes (there are in fact three plural forms of the word octopus) have 3 hearts! There are two branchial hearts, involved in pumping blood through each of the two gills, while the third heart pumps blood throughout the body. And they can obviously die of a broken heart(s) as reproduction is a major cause of death: males can only live for a few months after mating, and the females succumb shortly after their eggs hatch as they neglect to eat during the period spent taking care of these, and eventually die of starvation.