Blue-ringed Octopus

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Feeding

H. Maculosa feeds on mostly small crabs and shrimp. The octopus has two toxins in its body. One is more potent and used on attackers while the other one is used to stun prey in order to consume. The blue-ringed octopus either releases its venom into the water or catches its prey, chews a hole with its sharp beak like mouth, and ejects the venom straight into the body from the salivary glands.

Toxins: what makes them special?

H. maculosa create a deadly substance that can be fatal to man with one bite. This toxin is defined as a neurotoxin because it effects the nervous system, blocking nerve impulses and breaks down nerve tissue. Not only is it a neurotoxin, but a special kind called a tetrodotoxin (TTX). TTX is specifically a sodium channel blocker making it very potent and work very fast. Symptoms of getting bit by a blue-ringed octopus include paralysis and sudden stop of heart beat which ultimately causes death. These fatal neurotoxins are located in the octopus’s salivary glands and are ejected into another organism when the octopus is feeling threatened. H. maculosa also use their toxins offensively by stunning their prey.

What makes H. maculosa and other blue-ringed octopus species unique is that bacteria found in its salivary glands are involved in TTX accumulation. (et al. D.F Hwang) Not only is TTX detected in the salivary glands but also in the intestine and their eggs. The tetrodotoxins produced by bacteria are mainly used for protective reasons.

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Reproduction and Development

What makes H. maculosa interesting, as well as many other cephalopods, is that both the male and female die after mating only once. The male dies directly after mating, specifically after he has inserted his spermatophores into the female’s oviduct. The males have a “hectocotylus” a special arm used to insert into the female. After the eggs are laid, the female devotes the rest of her life to protecting her hatchlings. She will not leave the eggs or eat for months which ultimately leads to her death by the time the eggs are hatched. In an experiment done in lab (et al. H. Overath, S. von Boletzky) a female blue-ringed octopus actively rejected food while her hatchlings were still gestating and died three weeks after the last hatchling was born.

Major points in the juvenile blue ring octopus’s life is 1 month, where they are most likely to kill their first prey and 6 weeks, where they change their color patterns and can display their defensive blue rings.

The embryos turn inside their shells during development and hatch mantel first. They do not have a planktonic stage and resemble tiny, pea sized adults. It only takes 4-7 months for the H. maculosa larvae to reach full sexual maturity.

Folded open reproductive organ of female H. maculosa (D.J Tanter, O. Augustine)

Interesting facts

• • The blue ringed octopus carries enough poison to kill 26 humans in minutes.

• The blue ringed octopus is monochromatic, meaning it can only see in black and white

• Immediate symptoms of a blue-ringed octopus bite include: inability to see, numbness of tongue and mouth, extreme nausea, difficulty swallowing

• They are known to be cannibalistic

Work cited

Khalid, Waleed. “Blue Ringed Octopus Facts | Facts about Blue Ringed Octopuses.” Animals Time, 23 Sept. 2015,

Hwang, D F, et al. “Tetrodotoxin-Producing Bacteria from the Blue-Ringed Octopus Octopus Maculosus .” 1 Oct. 1989, pp. 327–332

Overath, H, and S von Boletzky. “Laboratory Observations on Spawning and Embryonic Development of a Blue-Ringed Octopus.” 9 Sept. 1974.

Tranter, D.J. “Observations on the Life History of the Blue-Ringed Octopus Hapalochlaena Maculosa.” ResearchGate, Jan. 1973,

Klijn, J. “Ongoing 2b/3a inhibition In Myocardial infarction Evaluation.” Http://Isrctn.org/>, May 2012, doi:10.1186/isrctn06195297.