The North Pacific giant octopus relies heavily on its highly developed senses; each of its four pairs of arms is covered with up to 280 suckers, and each individual sucker contains thousands of chemical receptors that give it an acute sense of touch and taste (4), which it uses to detect its prey (11). It is an active predator, feeding mainly at night on a wide array of species that include crustaceans (particularly crabs and lobsters), molluscs, small fish and other octopuses (2) (3) (8). Capable of using several different techniques to access the soft flesh inside its hard-bodied prey, the North Pacific giant octopus may pull apart the shell, or bite it open with its hard ‘beak’. Where a prey item is too difficult to be pulled or bitten apart, it may use a special drilling technique, whereby the salivary papilla, an organ that is covered in small teeth, is used to drill a hole in the shell and secrete a toxin. The toxin paralyses the prey and dissolves the connective tissue that attaches the animal to its shell, making it easier for the North Pacific giant octopus to feed on the contents inside (4) (8) (11).
The North Pacific giant octopus may reproduce at any time during the year, with a spawning peak during the winter months (3). Usually a solitary species, the male and the female will only come together for a short time during mating (2). The male has a specially modified arm, known as the hectocotylus, which is used to deposit a packet of sperm, called a spermatophore, inside the mantle cavity of the female (2) (3) (4) (8). After mating, the female will lay between 20,000 to 100,000 eggs over a period of several days. The eggs are laid in strings that hang inside a rocky den, and from then on the female will wash and aerate the eggs with a stream of water from the siphon, and will groom the eggs to ensure they remain free of parasites. Depending on water temperature (which controls the rate of development of the eggs), the incubation period can last up to eight months, during which time the female does not feed. The female dies shortly after the eggs hatch (2) (3) (4) (8).