Like other cephalopods, the octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the centre point of the arms (which are sometimes mistakenly called "tentacles"). The soft body can rapidly alter its shape, enabling octopuses to squeeze through small gaps.
An octopus has three hearts, nine brains, and blue blood. Two hearts pump blood to the gills, while a third circulates it to the rest of the body. The nervous system includes a central brain and a large ganglion at the base of each arm which controls movement.Aug 22, 2012
Well, the cephalopods—that's the octopuses, squids and cuttlefish—they are unique in that all these ganglias have condensed so they form a centralized brain. ... What's interesting about the octopus is about one third of the neurons (nerve cells) are in the brain.Feb 27, 2009
As with most creatures, the octopus's main purpose in life is to reproduce. However, if it knew just what was waiting for it soon after, it might think twice. Both the male and female octopuses die soon after mating. The male dies a few months afterwards, while female dies shortly after the eggs hatch.