Octopus Facts

By Author: Steve Whitehead
Total Articles: 9
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Octopuses belong to the class (sub-group) of cephalopods, which also includes squids, cuttlefish and the very rare nautilus. They have a relatively short life expectancy, and some species live for as little as six months, with the norm being approximately two years. They are found in every ocean of the world, in almost every depth. They are part of the Mollusc family, more closely related to Pipis and Mussel than fish.

Giant Pacific octopus are the world's largest species of octopus and are found from Japan to Southern California. They (and other molluscs) have blue blood. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen.

They draw water into their mantle cavity where it passes through its gills. Their arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. They can use muscles in the skin to change the texture of their mantle in order to achieve a greater camouflage. They also have an excellent sense of touch. Octopuses move about by crawling or swimming. They swim by expelling a jet of water from a contractile ...
... mantle, and aiming it via a muscular siphon.

They are also quite strong for their size. They have no bones or shell, so their arms are completely flexible. They often escape even from supposedly secure tanks, due to their problem solving skills, mobility and lack of rigid structure. They kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. An adult Octopus can squeeze through a hole the size of a 10-cent coin.

Octopuses can survive for short periods out of water, as long as their gills stay wet. They feed chiefly on crabs, clams, and snails.

Octopuses are probably the most intelligent creatures outside of the vertebrate phylum to which we humans belong (which includes fish, amphibians, reptiles, birds and mammals). They are curious and intelligent, as befits their role as hunters and are probably the most "intelligent" of invertebrates and have been shown to have the ability to learn from experience. It has been estimated that they are as smart or even smarter than dogs.

Octopus are highly mobile predators that use their eight arms to crawl swiftly across the bottom. They are often confused with squid, another Cephalopoda which has two longer arms called ‘tentacles' - in an octopus all eight appendages are of a similar length and are called ‘arms' not legs.

They are virtually invisible when they are hiding, as they match the colour and pattern of their background exactly. Octopus have the ability to change color at a whim. They have no discernible hearing organs of any sort and do not appear to use sound for communication.

Octopuses travel head first with their arms trailing behind them. They only mate once during their life, live alone and, like the squid, some species can shoot ink and change colors.

Many species of octopus are eaten as food by human cultures around the world. Between 20,000 and 100,000 tonnes of common octopus are caught every year throughout the world.

Only a few types of octopus are venomous enough to kill a man, and these are easily identified by the speed at which marine biologists flee from them. Blue-ringed octopus are thought to harness bacteria in their salivary glands to produce tetrodotoxin found in poisonous puffer fishes.

The main environmental threats to the common octopus are related to the destruction of its habitat or a reduction in its main diet of mollusks, crayfish, and crabs through excessive fishing or marine pollution. In fact, giant octopus are shy and pose little danger to divers, fishermen, and swimmers.
Kevin conducts Party Wall Surveys, and deals with Party Wall Agreements. In his spare time he enjoys scuba and freediving.