Octopus -- Intelligent Invertebrate

The octopus is a cephalopod that inhabits many diverse regions of the ocean, especially coral reefs.

Octopuses have two eyes and four pairs of arms usually bearing suction cups. An octopus has a hard beak, with its mouth at the center point of the arms. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places.

Octopuses are highly intelligent, probably the most intelligent of all invertebrates. The exact extent of their intelligence and learning capability is much debated among biologists. However, maze and problem-solving experiments have shown that they do have both short- and long-term memory. The octopus is the only invertebrate which uses tools.

Octopuses have a relatively short life expectancy, and some species live for as little as six months. Reproduction is one of the causes of death: males can only live for a few months after mating, and females die shortly after their eggs hatch.

Octopuses move about by crawling or swimming. They crawl by walking on their arms. Octopuses swim by expelling a jet of water.

An octopus¡¯s main (primary) defense is to hide. The most common secondary defense is fast escape. Most octopuses can eject a thick blackish ink in a large cloud to aid in escaping from predators. The main coloring agent of the ink is melanin, which is the same chemical that gives humans their hair and skin color.

Humans eat octopus in many cultures. The arms and sometimes other body parts are prepared in various ways, often varying by species. Octopus is a common ingredient in Japanese cuisine, including sushi and takoyaki. Octopus is also a common food in Mediterranean cuisine and people eat octopus regularly in Hawaii.