Greater Blue-ringed Octopus

• fisiologíaFor all its small size it produces one of the most potent toxins known in the animal kingdom, able to cause respiratory paralysis in people, and there is no specific antidote.
• It is one of the most toxic marine animals in the world, and it fits in the palm of a hand: it does not exceed 10 cm including the arms and weighs about 80 grams. A single individual carries enough tetrodotoxin to kill several adults.
• Tetrodotoxin is the same neurotoxin found in pufferfish, and it blocks the action potentials of nerves and muscles. There is no antidote.
• It does not make the toxin itself: it is produced by symbiotic bacteria housed in its posterior salivary glands.
• Its sixty blue rings appear only when it is disturbed, and then they pulse. At rest it is an unremarkable brown octopus.
• In exchange for that chemical defence it lost another: its ink sac has shrunk and it barely uses it.
• The female broods the eggs among her arms and dies when they hatch.

Skeleton type

Invertebrate - no rigid skeleton (mollusc)

Habitat and environment

Intertidal pools and coral reefs of the Indo-Pacific, from Japan to Australia; it hides in crevices, empty shells and tins

Sources consulted: Wikipedia (es): Hapalochlaena lunulata · Anatomia de Cephalopoda · Wikipedia (Cuttlebone, Gladius) · FAO, terminos tecnicos de cefalopodos