Octopuses are a row of cephalopods, eight-armed molluscs, to which about 300 species have been classified. They are two-side symmetrical animals, with two eyes and a beak, the mouth is in a central point with respect to the arms, sometimes incorrectly called "feelers". The soft body can change shape quickly. For swimming, the mollusc uses a siphon, through which it ejects water, the head is at the front, erected. The siphon also serves to exchange gas. The complex nervous system is associated with great eyesight in most species, octopuses are also among the most intelligent invertebrates presenting the most complex behaviors. They inhabit diverse regions of the oceans, including coral reefs, pelagic waters and the seabed. Some live in the interstate zone, others inhabit abisal. Most species are characterized by rapid individual growth, early maturation is accompanied by a short life. During breeding, the male uses a special arm to transfer the sperm pack directly to the female mantle, after which he grows old and dies. The female lays fertilized eggs in the den and takes care of them until the young hatch, and then also die.
