Saturday, September 18, 2010

September 18, 2010 : Giant Pacific Octopus

Giant Pacific Octopus

The North Pacific Giant Octopus (Enteroctopus dofleini) is a large cephalopod belonging to the genus Enteroctopus. It can be found in the coastal North Pacific, usually at a depth of around 65 meters (215 ft). It can, however, live in much shallower or much deeper waters. It is arguably the largest octopus species, based on a scientific record of a 71 kg (156.5 lb) individual weighed live. The alternative contender is the Seven-arm Octopus based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb). However, there are a number of questionable size records that would suggest E. dofleini is the largest of all octopus species by a considerable margin.

The North Pacific Giant Octopus, or the Giant Pacific Octopus, are distinguished from other species by their sheer size. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). However, there are highly questionable records of specimens up to 272 kg (600 lb) in weight with a 9 m (30 ft) arm span. The mantle of the octopus is spherical in shape and contains most of the animal's major organs. By contracting or expanding tiny pigment-containing granules within cells known as chromatophores in its tissue, an octopus can change the color of its skin, giving it the ability to blend in to the environment.

This species of octopus commonly preys upon shrimp, crabs, scallops, abalone, clams, and fish. Food is procured with its suckers and then crushed using its tough "beak" of chitin. They have also been observed in captivity catching Spiny dogfish (Squalus acanthias) of up to 3-4 feet in length. Additionally, consumed carcasses of this same shark species have been found in Giant Pacific Octopus middens in the wild, providing strong evidence that these octopuses prey on sharks in their natural habitat.

Marine mammals such as Harbor Seals, Sea Otters, and Sperm Whales depend upon the North Pacific Giant Octopus as a source of food. The octopus is also commercially fished in the United States.

The North Pacific Giant Octopus is considered to be short-lived for an animal its size, with life spans that average only 3-5 years in the wild. To make up for its relatively short life span, the octopus is extremely prolific. It can lay up to 100,000 eggs which are intensively cared for by the females, who die protecting the eggs. Hatchlings are about the size of a grain of rice, and only a very few survive to adulthood.

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