Octopus

Octopus.
The octopus is a soft-bodied, eight-armed mollusc of the order Octopoda, with around 300 known species. Along with squids, cuttlefish and nautiloids, they are classed as cephalopods. The mouth with its hard beak is at the base of the arms, which trail behind the animal as it swims. A siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates. They inhabit all parts of the ocean, from the intertidal zone and coral reefs to the abyssal depths. They can escape from predators by hiding in a cloud of ink, camouflaging themselves, or contorting their bodies to squeeze through narrow gaps. They are all venomous, but only the blue-ringed octopus is known to be deadly to humans. Octopus is sold as food around the world, especially in the Mediterranean and along the coasts of Asia.