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Friday, Aug. 23, 2002


Common octopus

* Japanese name: Madako
* Scientific name: Octopus vulgaris
* Description: Octopuses are cephalopods, the most complex and advanced of the mollusks. They have short, round bodies and, of course, eight arms joined by a web of skin. The arms are covered with suckers. Octopuses move by jet propulsion, by squirting water from a funnel-like opening in their bodies. In Japan, the common octopus grows to between 60-90 cm long; females weigh about 5 kg, males 6-8 kg.
* Where to find them: All around Japan, usually at the bottom of the ocean. They spawn twice a year, around April/May and again in October. Females lay around 250,000 eggs, which hatch into plankton and float on currents for about a month before settling onto the seabed. In Japan, around 45,000 tons of octopus are caught every year.
* Food: Crabs and lobsters, which are caught in their arms and devoured with the help of a sharp, beaklike mouth.
* Special features: Many zoologists consider octopuses to be as intelligent as dogs, and they certainly have the most complex brain of all invertebrates. Octopuses have long- and short-term memory and solve problems by trial and error. Once solved, octopuses use the experience to solve similar problems in the future in the same way. When they are threatened, octopuses have a couple of surprises to help them escape. They can release a cloud of ink (they have enough stored for several emissions) and jet away under its cover. This defense must be used carefully, however, as if the octopus is stuck in a cave without adequate water flow, when it releases its ink it may sicken or even die because the ink has toxic effects. The second trick is chameleonlike: octopuses can change color to match their surroundings.

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