Octopus

Octopus refers to any member of the order Octopoda, a group of soft-bodied marine mollusks in the class Cephalopoda. Most octopuses belong to the family Octopodidae. They are characterized by a bulbous head (mantle), eight flexible arms lined with suction cups, a beak, and, in many species, a highly developed nervous system. The body lacks a rigid skeleton, allowing extraordinary flexibility and the ability to squeeze through tight spaces. Water is expelled from the mantle through a siphon to propel the animal by jet propulsion.

Octopuses are carnivorous and primarily feed on crustaceans, mollusks, and small fish. They use problem solving and exploration to locate prey. They have complex behaviors and show learning, short- and long-term memory, and sometimes use tools. Their eyes are well developed and resemble vertebrate eyes.

Defense relies on several mechanisms: rapid escape, camouflage using chromatophores, iridophores, and papillae to change color and texture, and the release of ink to obscure predators. Some species have venom that helps immobilize prey.

Reproduction is typically seasonal. In many species the female guards eggs until they hatch and dies afterward; most octopuses have short lifespans, often about one to two years. They inhabit diverse habitats from shallow coastal waters to deep sea, with a worldwide distribution in temperate and tropical seas.

Human interactions include fisheries, cuisine in some cultures, and research into neural and behavioral biology. Conservation status varies by species and region, with threats including overfishing, habitat destruction, and pollution.