Life Of Octopus Dofleini Essay, Research Paper

Life of Octopus Dofleini

Introduction

This is a research report on octopuses in general, however will focus in

on a particular species of octopus, the North Pacific Giant or octopus dofleini ,

which is a bottom dwelling octopus that lives on coasts of the pacific ocean,

from California to north Japan. This report will cover the habitat, and

lifestyle of this amazing mollusk, that is so often misunderstood. The octopus

is a very intelligent, and resourceful invertebrate whose natural abilities

should make this a fairly interesting reading.

REPRODUCTION OF O. DOFLEINI

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 any where 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 OF O.DOFLEINI

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.

THE DEN OF THE OCTOPUS

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 OF THE OCTOPUS

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 AND PHYSICAL ATTRIBUTES OF OCTOPUS

As in other aspects of the octopuses 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 octopuses body is the beak,

this allows octopuses to fit through holes no larger than the beak its self.

All octopus 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 its 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.

THE MIGRATORY HABITS OF O. DOFLEINI

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.

O. DOFLEINI AND MAN

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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