Last updated: May 25, 2018 at 16:57 pm
Blue-ringed octopus (genus Hapalochlaena) — This small cephalopod measuring 2 to 20 cm (0.8 to 8 in.) and weighing 10 to 100 g (0.35 to 3.5 oz) injects the neurotoxin tetrodotoxin contained in its saliva when it bites into its prey, which mostly consists of small crabs. The venom, for which there is no antivenom, causes paralysis, respiratory arrest, and possibly cardiac arrest. A single octopus reportedly carries enough venom to kill several adult men. Fortunately, the blue-ringed octopus is not an aggressive animal and it does not seek contact with divers. Nonetheless, it may on rare occasions bite and thus incapacitate—or even kill—a human if it feels threatened or in the case of accidental contact. As a result, less than 20 people are believed to have died from such bites throughout the octopus’ range during the last century. At least 10 species of blue-ringed octopus are found in tidepools and shallow water from Japan to Australia.
Jacups, Susan & Currie, Bart. (2008). Blue-ringed octopuses: a brief review of their toxicology. Northern Territory Naturalist. 20. 50-57.
Williamson, John A. (1996). Venomous and Poisonous Marine Animals: a Medical and Biological Handbook, UNSW Press.
Please note that comments are moderated: (1) Stay on topic (2) Be respectful (3) Refrain from vulgarity and abusive language (4) Do not make personal complaints about a person’s character, business, work or associations (5) Do not publish materials that violate copyright. OFFENDING COMMENTS WILL BE DELETED.
If you have claim to a diving or underwater record or first, if you know of a significant first or record not listed here, or if you can demonstrate that any of the information on this website is false or outdated, please complete the form on the record submission page.
In order to ensure your browsing experience is as enjoyable as possible, banners are kept to an absolute minimum, which means that advertising revenues alone cannot sustain this 100% FREE publication. Researching and updating the Diving Almanac requires a lot of time and dedication. If you believe the diving community needs a central body of information to record, validate and make available our shared history and accomplishments, please show your support by making a contribution to the Diving Almanac via PayPal (Porbeagle Press). Thank you!
Jeffrey Gallant is the Editor-in-Chief and Records Keeper of the Diving Almanac. He is also a contributing editor of DIVER Magazine, and the scientific director of the Greenland Shark and Elasmobranch Education and Research Group (GEERG). Jeffrey started diving in 1982.