The Giant Pacific Octopus

The Giant Pacific Octopus (Enteroctopus dolfeini) is the largest of all octopus with an average span of 5m and weighing 100lbs, though the largest discovered was reported to of grown to an arm span of 9.1m and weighing more than 600lbs [1]. They live for around 3-5 years and are mostly solitary creatures. The Giant Pacific Octopus is common to the northern Pacific, in the intertidal zones to depths of nearly 2,500 feet [2].

Diet and Hunting behavior

The main diet of the Giant Pacific Octopus revolves around crustaceans and small fish, however octopuses are known for cannibalism and have even been known to catch and kill sharks. Like most octopuses the Giant pacific octopus is a nocturnal hunter, and use ambush techniques utilizing its highly developed brain, acute vision and its incredible ability to camouflage itself against its surroundings, or it actively seeks out crustaceans in crevasses using its arms which each are covered in an average of 250 suckers which are highly sensitive to both touch and taste [3]. Once caught the octopus has a multitude of weapons to kill and devour its prey. The thousands of suckers an octopus possesses can collectively pull around 700 pounds [4], these all can be used to tear or crush prey using brute force. If the prey is to tough the octopus possesses a powerful beak to tear off chunks, or it can use an organ called the salivary papilla which is covered in small teeth and can bore into shells then delivers salivary secretions which further corrodes the shell and also separates the prey from its shell.

Predators

The main predators of the Giant pacific octopus consist of harbor seals, sperm whales, sea otters and large fish species such as Halibut or Ling Cod. To escape and avoid these predators the northern pacific octopus has developed multiple adaptations and traits. The octopuses skin contains pigments that can expand and contract to alter the colour and texture of the octopus to blend into its surroundings. Due to the octopuses lack of skeleton it is able to fit into very small crevasses, the size of which is dictated by only the size of the beak which is the largest solid part of the octopus. If the octopus is unable to hide it can fire a jet off water propelled through the syphon in the mantle, this is usually used in conjunction with a squirt of “ink” to momentarily distract the attacker while the octopus flees.

Breeding and Population numbers

The male octopuses third arm on the right for the last 4 inches is modified for breeding, it does not posses any suckers and is designed to insert ropes of sperm in to the females mantle cavity [5]. Once fertilized the female hangs the 100,000 eggs across the roof of her den, she then protects and tends to the eggs by cleaning and aerating them constantly without stopping to feed, though only 1 or 2 of these octopuses will grow to an adult. The female dies shortly after the eggs have hatched, during this time the male goes into what can only be described as a state of delusion, it wanders the area without camouflage, aggressively attacking anything in its vicinity, while also refusing to eat. During this time the male is likely to be eaten by predators or die due to starvation.

The Giant Pacific Octopus is currently unprotected, but this is largely because so little is known about them. However lately finding larger specimens has become rarer and rarer meaning that damage is being done to their population. However one thing we do know that affects the octopuses habitat, is that they are very sensitive to pollution [6].

References

[1] http://animals.nationalgeographic.com/animals/invertebrates/giant-pacific-octopus/

[2] http://www.aqua.org/animals_giantpacificoctopus.html

[3] http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cephalopods/FactSheets/Pacificoctopus.cfm

[4] http://seagrant.oregonstate.edu/sgpubs/onlinepubs/g07002.pdf

[5] http://seagrant.oregonstate.edu/sgpubs/onlinepubs/g07002.pdf

[6]http://nationalzoo.si.edu/Animals/Invertebrates/Facts/cephalopods/FactSheets/Pacificoctopus.cfm

Picture References

[1] http://animals.nationalgeographic.com/animals/invertebrates/giant-pacific-octopus/

[2] http://animals.nationalgeographic.com/animals/invertebrates/giant-pacific-octopus/

[3]http://gallery.photo.net/photo/

[4] http://animals.nationalgeographic.com/animals/invertebrates/giant-pacific-octopus/

8 years ago

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