How many hearts does octopus have

As if they wish to spread more love to the universe, octopuses are equipped with not one, not two, but three individual hearts! Each of these three hearts perform a unique function, which means that all three of them are equally necessary for the octopus. What exactly does each heart do? Let’s try to refresh our knowledge about biology and understand why the octopus needed to evolve two additional hearts. Three, Two, One…Go! All cephalopods have a heart above each gill (called the branchial hearts) and one central heart (the systemic one) which pumps the blood around the body. Octopuses need to increase their blood pressure in order to transfer oxygen to every single of their numerous functional muscles. But the blood cells of the octopus are rich in copper haemocyanin instead of iron haemoglobin. The copper-rich blood does not transfer the oxygen as effectively as iron-rich blood would. With less oxygen transferred through the blood, the speed of the octopus would decrease significantly as its blood pressure wouldn’t be high enough to motivate the muscles. The octopus would be, therefore, a much easier pray for its enemies, and might not have survived to this day. But the auxiliary branchial hearts receive the deoxygenated blood from the body and pump it through the two gills and back to the systemic heart. At the same time the systemic heart keeps the blood circulation flowing for the organs. Are you a bit confused by now? More simply put: No hearts, no speed, no octopus...