Blue Ringed Octopus Description

The blue ringed octopus is a soft bodied organism which belongs to the Class Cephalopoda (which means 'head and foot' animal). For the octopus, along with other Cephalopods such as cuttlefish and squid, the foot has become tentacles.


The blue ringed octopus is usually light brown to dark yellow in colour but it rapidly changes to vivid yellow-brown with iridescent blue rings when agitated. It can grow to a maximum length of 20 centimetres when the tentacles are stretched out and weigh up to 100 grams, depending on the species.

The 'head' or mantle of a blue ringed octopus is surrounded by eight muscular tentacles, partially joined by a 'skirt', that radiate out from the body and encircle the beak-like mouth parts. The beak is one of the only 'hard parts' of an octopus so they are able to squeeze through tiny holes and into small crevices.

The mantle contains the organs and gills of the blue ringed octopus. Water is pumped in and out of the mantle as air is passed across the gills. Water is also forced out through the siphon to provide jet propulsion.

Each tentacle bears two rows of whitish suckers on the inner surface that can move independently. The tentacles are strong enough to prize open bivalve shells. If a tentacle is damaged or lost, it can be regenerated.

Other Features

The blue ringed octopus has well developed eyes with an image-forming lens and large retina. It is thought that their vision is only black and white.

The blue ringed octopus is very intelligent. They have displayed the ability to learn as well as problem solving skills. The blue ringed octopus, like other octopus are deceptively strong and can escape from confinement if the container is not properly secured.

The blue ringed octopus has poison glands that secrete two different types of poison: a mild type for catching food and a very poisonous type for defence.

Website created by Jenny Stevenson - June 2006.