Octopuses have 3 hearts, because two pump blood to the gills and a larger heart circulates blood to the rest of the body. Octopuses have 9 brains because, in addition to the central brain, each of 8 arms has a mini-brain that allows it to act independently. Octopuses have blue blood because they have adapted to cold, low oxygen water by using hemocyanin, a copper rich protein. We know that octopuses are intelligent, because they like to play and use tools – but we have no way of relating to what it would be like to have 9 brains. The central brain is a doughnut shape that forms a ring around the esophagus, so when an octopus swallows, its food must ‘pass through’ the brain! What a concept! Food for thought…?


The most interesting thing is that they have a mini brain in each arm. This adds up to a lot of distributed brain power. Since each arm has a mini brain, the central brain just sends a higher-level signal to the arm; something like “move to crevice for possible crab.” In our case, our brain would guide and control each movement of our arm. With an octopus, the arm acts almost independently as it proceeds to probe into the crevice, tasting and feeling with its suckers.