The octopus is a member of the molluscan class Cephalopoda, which represents the maximum evolution of these invertebrates.
Usually, the octopus crawls on the bottom, using the suction cups that cover its eight tentacles and hiding on the bottom or among rocks. When it feels threatened, it can swim swiftly by propulsion, expelling water from the mantle cavity, through the 'siphon', a tube located on the side of the head.
One of the most interesting aspects of its biology concerns its extremely short life cycle: from 12 months to a maximum of 3 years. For this reason, the octopus develops extremely fast, and the animal can reach 10 kg in weight during this period.
The male dies after reproduction and the female lays her eggs, whose number varies between 100,000 and 500,000, in rocky cavities, empty shells, etc. She then quits feeding and watches over the eggs until the octopus babies hatch (weighing, on average, 0.001g), and then dies.