The spawning of the giant pacific may occur at any time of the year; however the mating of the octopus peaks in the winter months, with the peak of egg laying in April and may.  Octopuses reproduce sexually, and have both male and female octopuses.  Reproduction takes place as follows:  The male octopus uses his tentacle to take a mass of spermatophore from within his mantle cavity; he then inserts it into the oviduct, in the mantle cavity of the female.  This process occurs at depths from 20-100m and, lasts hours.  With female octopuses receiving spermatophore up to 1m long.

Female octopus seem to prefer larger males as mates and male octopus may mate with more than one female in their life span, however the male octopus only lives a few months after breeding, and the female will die shortly after the eggs hatch.

Incubation can take from 150 days to seven or more months.  The female may produce anywhere from 20,000 to 100,000 eggs over a period of several days.  During incubation the female octopus will take to cleaning and aerating the eggs.  This takes place at a depth of less than 50 meters

Life Span

After hatching, the baby octopus(or larvae) take on the role of plankton, drifting around the ocean feeding on neuston (dead food) as opposed to hunting live prey.  This stage on an average lasts for 30-90 days.

Without mating the octopus may survive up to five years, and Giant Pacific octopus have been found to reach a weight of 600 pounds, and an estimated width of over 31 feet, But the average size is only 100 pounds and 3m, still weighing in as the largest species of octopus.

During their life span, many octopus fall victim to fatal, and non-fatal predation.  Therefore a high percentage of octopus are mutilated or missing arms, this percentage increases in octopus that live in deep water, perhaps this is because older octopus tend to occupy deeper waters and would naturally have more battle scars.  However larger octopus are less prone to these injuries.  Among the predators of octopus are, other octopus, sea otters, seals, sea lions, and fish.

Octopus  Den

In finding a den an octopus is a very resourceful animal.  Although most octopuses prefer to make natural rock crevices, and underground caves their dens smaller octopus tend to excavate areas of sea floor to build their own den, and still other octopuses prefer to occupy man made dens, such as ship wrecks.  Although the octopus is not territorial, and may only occupy a particular den for a few weeks at a time, the den seems to be a important aspect of the octopuses life.  The octopus uses its den for hatching its eggs, feeding, and even retreats to its den to hide from predators such as other octopuses, and seals.  A common site marking the entrance to an octopuses den is a pile of shells, and other refuge discarded after feeding.  Although dens are an important place to the octopus, octopuses are very mobile animals.

Feeding Habits

Octopuses feed on everything from smaller octopus, to crustaceans, but a favorite food appears to be crab, and shrimp.  As a general rule octopuses hunt prey during hours of darkness, and retreat to their den to feed.  Many octopus over take prey with use of venom of varying strengths, while others simply capture prey and consume them with their bird like beak.

Lifestyle & Attributes

As in other aspects of the octopus’s life, it is very resourceful, and interesting in its defenses and hunting techniques.  Some species of octopus, such as the Blue ringed variety (Hapalochlaena lunulata) Are deadly poisonous to man.  This octopus can administer its poison in two ways, it can either bite with its bird like beak, or release its poison into the water surrounding its prey.  This poison attacks the nervous, and respiratory systems of man, causing death in roughly one hour.  There is no known anti-venom, so the only way to survive an attack is through the administration of CPR until the poison wears off in several hours.  It should be noted that the primary use of this poison is in hunting prey, not defense.

Octopus have the ability to change their skin coloration (like a chameleon) in order to camouflage themselves.  This is accomplished through action of the chromatophore cells in the skin.  Chromatophore cells are made up of three bags containing different colors.  These colors are adjusted until the background color is matched.  The normal color of the North Pacific Giant is brown, however the octopus can change color according to mood, Red representing anger, white representing fear, and surely there are more moods with colors to match which are more subtle.  This ability to change color according to mood was for several years doubted by the scientific community, but is today a common belief.

The skin of the octopus is of varying softness, but all octopuses have very soft bodies. In fact the only hard part of the octopus’s body is the beak; this allows octopuses to fit through holes no larger than the beak its self.

All octopuses have the ability to shoot out a jet of purple, to black inky fluid from under their eyes, in order to perform a disappearing act when they feel threatened.  The octopus can shoot out several blotches of this fluid before the fluid sac is emptied.  This trick is not always an option, the ink is actually toxic to the octopus, and if shot in a confined area, the octopus will become sick or even die.

Octopuses have fairly good eyes; in fact they are comparable to ours in clarity.  The eyes of the octopus differ from ours, in the respect that they focus by moving in, and out.  Whereas the human eye focuses by changing the shape of the lens it’s self.

The octopus posses the most advanced brain of all invertebrates, with both short and long term memories.  This allows the octopus to learn in much the same way as humans, through trial and error.  When an octopus learns a lesson it remembers and puts its knowledge to use in the future.  The octopus has eight arms, with 250 suckers on each arm for a total of 2000 suckers on their body.  These suckers are very sensitive to touch; in fact, the octopus can differentiate between different objects just as well with their suckers as they can with their eyes.  Some species have particular suckers that are larger than the rest, This is to aid in reproduction.  Although octopuses often lose arms to predators, it is of no consequence as the arm will grow back in a short time.

The Pacific Giant Octopus is of the phylum mollusca, class cephalopod, order octopoda, family octopodidae, and their closest relatives are the chambered nautilus, squid, and cuttle fish.  The squid is in many ways similar to the octopus.  The squid (like the octopus) changes skin color according to mood and background, and The feeding activities of the planktonic O. dofleini are described as squid like darting.

Migratory Habits

The medium to large pacific giant is believed to go through a migratory stage in which it migrates from shallow to deep water and back again, the migratory cycle runs as follows:  shallow water  October-November/deep water February-March/shallow water April-May/deep water August-September.

Commercial & Hunting

The pacific giant is the most common commercial species of octopus and is caught by fisheries from north Japan to Washington state.  The octopuses are caught in large sometimes clay pots and raised to the surface.  The octopuses are used for bait and for consumption by humans.  Although these octopuses are caught in nearly all of their habitats, they are not endangered.

The ocean is where life began, and is a far more competitive, and harsher world than the world we know.  So it comes as no surprise that the most advanced and well adapted life forms would be found in the ocean.  Although octopuses do not build large structured civilizations, they are obviously another form of intelligent and highly adapted life forms.

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1 Comment on "Giant Pacific Octopus: Reproduction, Life, Habitat, Migration, Hunting"

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Gary K. Greer
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Hello.

I am writing an article for a university e-journal titled “Interchange” that summarizes topics in science for regional (Michigan) secondary teachers (K-12). I am writing an article that summarizes life history evolution and would like your permission to use your photo of the giant Pacific octopus (the one in the tank).

Gary K. Greer, Ph.D.
Associate Professor
Biology Department
Grand Valley State University
Allendale, MI 49401-1000

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