The octopus is a sea animal that with a round body, and eight long arms. There are at least 100 species of octopi. The best-known species lives in rocky, or muddy bottoms in shallow parts of the ocean. Other octopi live in deeper waters.

    Octopi come in many different sizes. The Giant octopus, largest species, live in the Pacific Ocean. They can weigh 110 pounds when   fully grown, and measure more and up to 20 feet from the tip of one arm to the tip of another arm on the other side of the body.

    The smallest octopus lives in the Indian Ocean, weighs less than 1 gram, and is only 1 inch from the tip of one arm to the tip of another on the opposite side.

    Octopi have no bones. They are covered by mantle. The mantle is the muscular covering on the outside of an octopus. Octopi have three hearts. Each gill has a heart that's called the gill heart. Octopi vision is about the same as a human's. Octopi have eight arms. The arms are all lined with extremely strong suction cups. An octopi uses these suction cups to maneuver along the ocean floor, and capture its prey.

    Octopi usually feed on shell fish, such as, clams and snails. They use their strong beak to puncture the shell of its prey and suck out the contents.

     An octopus's predators include seals, whales, and certain sharks. The octopi have many ways of staying away from their predators. It can swim quickly by forcing a jet of water through its funnel. Also, it will hide itself in a cloud of ink. Species of octopus can change colors rapidly to confuse their predators.

    Female octopi lay as many as 100,000 eggs. The mother octopus cares for the eggs until they hatch into baby octopi. The baby octopi disguise themselves among the plankton. Many of them are eaten by predators. The remaining feed on plankton until they become to heavy too float, then they sink to the bottom and grow to their full size.

    The life span of an octopus is short. The largest species of octopus live the longest at three years. The rest of the species live an average of one year.

    Octopi are usually not considered dangerous, but some do bite. Take extreme caution when near an octopus. Some countries consider octopus meat a delicacy.     

     In some countries, octopus is an important food. There are many octopus fisheries in the world, mostly off Japan, on the Mediterranean, and off the Northwest coast of Africa.