Critter of the Month

Critter of the Month April 2018

Critter Facts

Common name: 

Day Octopus

Scientific name: 

Octopus cyanea

Critter contributor: 

Doug Finney, Flickr. 


The Octopus cyanea is an incredibly interesting and unique species of cephalopod. Known for its athleticism and diurnal feeding habits, the O. cyanea differs from most nocturnal octopuses. Hunting excursions of this octopus have been recorded as lasting up to one hour and extending up to 50m away from the creatures’ home. Like many other species of octopi, the O. cyanea creates a den for itself where it will remain protected during the night – coming out to feed at dawn and dusk. The O. cyanea is carnivorous and hunts small crabs, lobsters, snails and small fish. After it captures its prey, the octopus will bring its capture back to its den, kill it by secreting venom from its salivary glands and crack the shell of crustaceans and molluscs by using its sharp beak. Much like adding butter to escargot at a fancy French restaurant, the O. cyanea may also drill a hole in its prey’s shell with its radula and deposit a chemical into said hole that separates the prey’s meat from its shell. The octopus then deposits the empty shells outside its den – a phenomenon colloquially referred to as an “octopus’s garden”, or a midden.

Like most other octopi, the O. cyanea is equipped with superb camouflage skills, which are even further enhanced through evolution due to the octopus’s diurnal feeding habits. The O. cyanea is capable of not only changing its pigmentation to match the substrate under it via chromatophores in its brain, but can also utilize mimicry – giving its skin a rough, bumpier appearance to imitate surrounding corals or rocks. The octopus has also been recorded as producing a “passing clouds” effect wherein it creates the effect of a shadow passing over its body so as to convince nearby prey of the octopus’s seemingly inanimate nature.

Like all other cephalopods, the O. cyanea are gonochoric – they are either distinctly female or distinctly male and will reproduce sexually. The male O. cyanea will try to impress his lady O. cyanea of choice with a showy display of pigmentation changes, movements and specific courting behaviors. If said lady should enjoy this display of male prowess, the two copulate - an activity involving the male grasping the female and inserting his hectocotylus (a modified arm used to transfer sperm into a female) into the female’s mantle cavity. The sperm gets released and the fertilization begins. The female will hatch the embryo into a planktonic state wherein her little octopi babies will reside, pelagic drifters, prior to growing larger and taking on their benthic adult states.




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