Giant Pacific octopus

Enteroctopus dofleini

Description: The Giant Pacific octopus (Enteroctopus dofleini) is usually reddish-brown in color, has a sack-like body and a bulbous head with two eyes, one on each side. The spherical body (mantle) contains most of its vital organs and the sharp, beak-like mouth that is used to kill its prey. It has four pairs of arms with suckers that extend from the mantle. Each arm has two alternating rows of suckers, about 280, that contain thousands of chemical receptors. It is able to change color and texture of its skin by contracting or expanding tiny pigments (chromatophores) in its cells, thus giving it the ability to blend into its surroundings.

Size: This octopus is one of the largest species of octopods. Adults weigh 50 to 90 pounds (22.7 – 40.8 kg) and have an arm span up to 16 feet (4.9m). The record weight for a Giant Pacific octopus is 600 pounds (272 kg).

Behavior: The Giant Pacific octopus is an extremely intelligent creature. It uses its well- developed sense of sight to learn through observation, is able to solve problems by trial-and- error and experience and has long and short-term memory. It is a solitary, timid creature and will often stay in its den for long periods of time, coming out only to eat, breed or escape danger. When threatened, the octopus can change color to conceal itself. It can also release a cloud of purple- black ink to confuse its predator.

Diet: This octopus is a forager. It mostly eats crabs and scallops, but will also consume abalone,
clams, fish, shrimp and squid. There are three methods of obtaining food that has been observed. The first method is pulling the shell apart to get at the ‘meat’; the second is crushing the prey with its strong beak; the third and most common method is stabbing or drilling a hole into the shell and injecting its toxic saliva. The prey becomes paralyzed, the connective tissue dissolves and then it is pulled apart.

Senses: The sense of sight is well developed. Focusing is done by the lens moving in and out. The sense of touch and taste is acute. These two senses are facilitated by the thousands of chemical receptors in the suckers.

Communication: The octopus can rapidly force water out of its body, propelling itself backwards to escape predators and warn others that danger is near.

Reproduction: The third right arm of the male is hectocotylized (modified) with a modified tip called the ligula. He uses this arm to transfer sperm into the female’s oviduct. The female then lays 20,000 to 100,000 rice-shaped eggs in clusters over a period of several days. These clusters are usually hung from the ceiling of their den and the female remains with the eggs cleaning and aerating them until they hatch. The incubation period can take 150 days to seven or more months depending on water temperature. Cooler temperatures delay the development of the embryos. While the female tends to the eggs, she does not eat, therefore she dies once the eggs hatch or shortly thereafter. After hatching, the larvae move to the surface where they spend about 4-12 weeks in a planktonic stage. At the end of the stage they will settle on the bottom and undergo rapid growth. Females only breed once in their lifetime; males may breed with several females.

Habitat/range: The Giant Pacific octopus lives in dens or lairs, under boulders, rock crevices or caves. It hides in kelp forests. It is found throughout the Pacific Ocean from Baja California, north along the coastline, across the Aleutians and south to Japan.

Status: Not currently under the protection of CITES or the IUCN Red List.