Gloomy Octopus (Octopus tetricus)

The gloomy octopus is an invertebrate in the class Mollusca, which also includes snails, clams and squid, however unlike their close relatives are shell-less. Octopuses are cephalopod molluscs which are generally considered to be the most inquisitive and intelligent marine invertebrates. The gloomy octopus has a mottled brown and grey colouration with a rusty red colour lining the inside of each arm. They have a rounded body and head with characteristic eight arms that taper to a tip. The arms are uneven in length and each has two rows of suckers which are equipped with chemoreceptors, enabling the octopus to taste what it is touching. The gloomy octopus is one of the largest local octopus species, with an arm span of up to two metres. The octopus has three hearts, two of which pump copper-rich blood through each of the two gills, the third pumps the blood through the body. Similarly to cuttlefish, the gloomy octopus is able to rapidly change colour, display patterns and alter skin sculpture to impersonate seaweed while hunting, to merge into the background to avoid predation and to lure a potential mate for reproduction. Their colour and pattern changes are facilitated by the contraction of specialised skin cells; chromatophores contain the yellow, orange, red, brown and black pigment, iridophores give the reflective iridescence in green and blue hues and leucophores create the white patterning.