1. Robster, FCD says

    One of my favorite octopuses and my favorite venoms/toxins (depending on delivery method).

  2. JM Inc. says

    Keep your puses to yourself, mate. I prefer octopodes (yes I am pedantic enough to embrace usage of a word that was never in usage).

  3. Fernando Magyar says

    These Octopi are golden, with little rings of blue.
    Tetrodotoxin is it’s venom and quite deadly too.

    Tis the same poison that’s found in the Fugu fishes
    Which Sushi chefs try hard not to serve in their dishes.

  4. Dan J says

    The Blue-Ringed Octopus
    The only way to survive is hours of heart massage and artificial respiration until the poisin has worked its way out of the system. There is no anit-venom to date.

    No worries there, PZ. I won’t get anywhere near one of those things!

  5. Gwyrrdin says

    Enlighten the non-biologist-noobs who do read this blog :)
    Why not play with it? It’s probably poisonous, but does it bite? or do you only have to avoid eating it. And how big is it?
    gory details!

  6. says


    Yes, like all cephalopods, they can bite if handled. Blue-ringed octopus carry one of the most toxic (to humans) venoms in the world.

  7. clinteas says

    Things like that yellow one up there are the reason this man is not swimming in no ocean,no Sireee !

  8. says

    They’re so cute though! I once found one in a rock pool, that was fun (didn’t interact with it, though).

    Gwyrrdin: yes, it will bite, and it’s quite venomous with no antidote. (don’t want to spoil the surprise)

  9. nekouken says

    PZ, you’re cheating; that is very clearly a Wacky Wall-Crawler that some kid dropped in the alley behind the Ben Franklin.

  10. Duvenoy says

    A lovely, little Blue Ring!

    What a pity that they don’t get larger — then we’d really have a sea monster worth yarning about!

    Thanks once again for the eye-candy!


  11. maxamillion says

    This would be the scary part.

    “Tetrodotoxin poisoning can result in the victim being fully aware of his/her surroundings but unable to breathe. Because of the paralysis that occurs they have no way of signalling for help or any way of indicating distress.”

  12. says

    “despite its small size, the blue-ringed octopus carries enough poison to kill 26 adult humans within minutes”

    ok gory details enough…I am very happy to live in the Netherlands…the only scary creatures we have here are the christians on our government.
    Thanks for the replies.

  13. says

    Awesome choice of Cephalopod. These things inhabit the area where I grew up. Well the Southern Blue Ring Octopus does anyway.

  14. davem says

    So why do venomous creatures tell us that they’re nasty with colour? Why not shape or pattern? And why do the colours warn us off in the first place? And are there any creatures that use colours to warn us off, but they’re actually fooling us, because they aren’t actually poisonous? Seems like that would be an evolutionary ‘smart move’.

    Is it a case of big fish eats one brightly coloured dinner, regrets it, and afterwards, all brightly coloured meals are subsequently rejected?

  15. Clintsc9 says

    Ah. Nice to see one of our local denizens. These things are really pretty and very attractive to kids playing in rock pools.

    At least they are Natural.

  16. Cliff Hendroval says

    Bill Bryson said “Australia has more things that can kill you in extremely nasty ways than anywhere else”. This little guy didn’t even make his list!

  17. Dunc says

    And are there any creatures that use colours to warn us off, but they’re actually fooling us, because they aren’t actually poisonous?

    Loads of them – it’s called Batesian mimicry.

  18. says

    Bill Bryson said “Australia has more things that can kill you in extremely nasty ways than anywhere else”. This little guy didn’t even make his list!

    You’ve got to love this country.

    Though despite all our dangerous creatures, you’re more likely to get killed from a bee sting, and far more likely to die in a car accident.

  19. LaTomate says

    One of my favorite aspects of your blog, Paul :)

    (As well as your tales of Crackerjacking)

  20. Simon Coude says

    When I first looked at it, I thought it was a spider. A weird shiny deadly spider.

    Then I realized it was friday cephalopods, and I was reassured. It was just a weird shiny deadly octopus.

    I find it funny that males have a hard time seeing the difference between males and females when mating. It made me think of the way bed bugs mate, but less extreme.

    Bedbugs Reproduction

  21. Uncephalized says

    davem @ #19:

    You’re spot-on AFAIK. There are plenty of creatures out there that are not themselves poisonous, but which imitate poisonous/venomous creatures to avoid getting eaten. The example that springs to mind is the venomous coral snake, and its harmless doppelganger the scarlet king snake. The old rhyme “red to yellow, kill a fellow; red to black, venom lack” is a handy tool for people to remember which of these snakes is dangerous, but of course predators can’t remember little rhymes. There are also a bunch of insects that closely resemble wasps and other painful/dangerous insects to avoid being eaten.

    As for how these things evolved in the first place, it’s always about survival. If a poisonous frog can advertise its inedibility, it won’t get attacked in the first place, whereas if it is just poisonous with no warning, its predator might well die on eating it, but the frog is still dead. Once the predators have “learned” not to eat that specific animal, whether through evolved instinct or through actual learning from experience, it obviously becomes advantageous for other, non-poisonous animals to resemble the poisonous one and avoid getting eaten themselves. Every little step that makes a fly look more like a wasp, or a king snake more like a coral snake, makes it more likely that other animals will leave it alone, and more likely its genes get passed on.

  22. Apostrophe Avenger says

    The Apostrophe Avenger awakes and oozes from its den (actually Elf Eye’s alter-ego–not trying to be a sockpuppet here). It’s ‘its’ for the possessive pronoun, so it should be ‘Tetrodotoxin is its venom’. Sorry to be an English professor today. It’s just that I’ve seen this error a lot lately as I’ve been reading through the crackerjack posts. Okay, Apostrophe Avenger will now slither back into its den.

  23. Dave Godfrey says

    As well as Batesian Mimicry (non-toxic mimicking toxic species) you also have Mullerian Mimicry where two toxic (and often relatively unrelated species) look very similar. Heliconia butterflies are the classic example.

  24. amphiox says

    davem, any trait that distinguishes the poisonous animal to the senses of potential predators could be selected for and enhanced. So shape and texture are certainly possible, and as far as I know, used.

    Color has some specific advantages, though, because it is easier to spot and discern from a distance, and the farther away the predator recognizes the poisonous creature, the farther away it stays, the better it is for said poisonous creature.

  25. dNorrisM says

    There was a TV show where a diver (a researcher) evoked the threat response of one of these things. Blue chromatophores started flashing like neon tubes. I felt like jumping backwards out of my chair. It seriously freaked me out. I wouldn’t want to go near one, even if I’d never heard of them.

    You ozzies should splice their chrotomaphore genes into those cane toads.

  26. Dale G says

    The James Bond story Octopussy is named for The Blue Ringed Octopus which is the method of death in the story. In the movie the main character has a tattoo of The Blue Ringed Octopus.

  27. says

    But it’s pretty. Can’t I touch it just a little bit?

    Boy, that takes me back to grope-fests in side rooms at high school house parties.

  28. Sven DiMilo says

    Hi, Brownian’s-inner-14-year-old!

    Tetrodotoxin is very cool; it plugs up voltage-gated sodium channels like a cork in a bottle and shuts down all motor nerve activity. (That’s why your heart, with its own pacemaker, keeps beating, and your brain, safe behind the blood-brain barrier, is fully functional, but you can’t move skeletal muscles including those that ventilate your lungs.) It’s also found in Fugu (pufferfish) and the skin of some newts. if I’m not mistaken it’s actually of bacterial origin in all three kinds of animals.

  29. Blind Squirrel FCD says

    Yes, the venom is bacteria-derived, according to the ever authoritative wiki. The males do not appear to be aggressive, and I read somewhere that they were used as pets and lab animals for some time until an unfortunate incident demonstrated the error. The females appear very aggressive when guarding eggs.

    I have handled several octipi/octopuses without any problems. (southern Atlantic species) Squid bite, however. Every damn time.

  30. truth machine, OM says

    So why do venomous creatures tell us that they’re nasty with colour?

    So they won’t get eaten.

    Why not shape or pattern?

    Because bright colors stand out — what sorts of shapes and patterns did you have in mind? And because mutations produce color changes relatively readily, certainly as opposed to shape changes.

    And why do the colours warn us off in the first place?

    Well, usually prey camoflage themselves, not call attention to themselves. If it’s not hiding, there’s likely to be a reason. But you’re assuming that it’s bright colors per se that warn predators off … rather, they are readily recognizable.

    And are there any creatures that use colours to warn us off, but they’re actually fooling us, because they aren’t actually poisonous?

    See above. It’s not bright colors per se, it’s being recognizable, so what you get is mimicry.

    Seems like that would be an evolutionary ‘smart move’.

    Seems like. In fact, all of this is rather obvious with a little thought.

    Is it a case of big fish eats one brightly coloured dinner, regrets it, and afterwards, all brightly coloured meals are subsequently rejected?

    Most learning in “lower” species is evolutionary, i.e., “instinctual”, not cognitive. The fish doesn’t eat the poisonous dinner because it’s descended from fish that survived by avoiding things that look like that.

  31. Calilasseia says

    Ah, the Blue Ringed Octopus.

    A marine aquarium dealer not far from where I live had the interesting experience of seeing one of these emerge from a shipment of live rock for reef aquarium keepers. Basically, for those of you who aren’t aquarists, “live rock” is rubble from coral reefs with extant communities of small invertebrate organisms resident within the crevices, and a population of nitrogen cycle bacteria growing upon it, that adds to the colour and variety of a reef aquarium as well as providing a source of nitrogen cycle bacteria that are useful in keeping pollutants down to a minimum. Now most shipments tend to be checked beforehand for anything potentially dangerous such as this, but somehow, on this occasion, a Blue Ringed Ocotpus managed to evade scrutiny and turned up at the dealer’s. Needless to say, the staff were none too happy about having to deal with a lethally venomous octopus roaming around their live rock aquarium.

    However, if one takes proper precautions, it IS possible for an experienced reef keeper to contemplate taking on one of these creatures, but I emphasise strongly that extreme care with respect to handling is advised at all times, and that the aquarium be constructed in such a manner as to allow it to be partitioned during maintenance work, as a bite from one of these creatures will ruin your social schedule big time.

    One person who, however, may well be encouraged to play with these creatures is the individual featured in this Tasmanian news story:

    Yes, you read that correctly

    Rule 34 strikes again …

  32. DingoDave says

    It is important to realise that the blue rings don’t appear until after the octopus feels that it has been threatened.

    Because I live in Australia, (not too far from the beach) I have sternly instructed my 7 year old son that if he ever finds a small octopus in a tidal rock pool, that he is not to attempt to pick it up or to even touch it without coming to me first.

    I’ve encountered several of these little critters during my lifetime, and I have always treated them with the utmost respect. Stonefish on the other hand are far more difficult to detect, until you happen to step on one.

  33. amphiox says

    davem, at the risk of stating the obvious, I would also point out that the subject of this post does in fact use pattern as part of its warning signal, a pattern of blue rings!

    Also consider critters like rattlesnakes that use auditory signals.

    truth machine, I wouldn’t be surprised if at least some fish actually do learn, as opposed to be hardwired from birth. The predators’ avoidance of the signal can arise from any number of causes, genetically preprogrammed behavior, learning from prior experience, learning from imitation, learning from being taught. For one particular species of upright biped predators, whole social taboos/religious customs have been known to arise as a response to these signals.

    (Though scaring H. saps too much has turned out in recent years to be a sometimes not so effective evolutionary strategy.)

  34. Paul Murray says

    I heard that these things cause passive paralysis – everyone thinks you are dead, but you quite aware. Autopsy horror.

    Don’t know if it’s true or not.