The New Most Venomous Creature in the World

You will already know if you have read my entire blog, (you have read my entire blog, haven’t you?) That the most venomous creature in the world is the box jellyfish. I told you all about him on September 10, 2009.

Now, I really didn’t want to tell you this, but I have decided I must break my silence. After all, I’d rather you heard it from me than from somebody else.

Some time in October 2009, I would imagine only about six weeks after making my box jellyfish post, I watched a TV programme on the Discovery Channel about killer jellyfish. I think it was called “The Silent Assassin” or something. I was expecting to hear more stuff about the box jellyfish. But instead I heard this……

  • A tiny predator the size of a thumbnail.
  • Almost impossible to see with the naked eye.
  • A sting that leaves no mark on the body.
  • Its sting is mild and can even go undetected by the victim.
  • Until Irukandji Syndrome hits, typically about 30-40 minutes later.
  • Then it becomes “five times more painful than childbirth” according to one victim.
  • Two people were killed by it in 2002.

It is now believed to be more venomous than the box jellyfish. MORE VENOMOUS!

So, meet the new most venomous creature in the world, the Irukandji.

Being so small, pictures of the Irukandji are rare, but I decided to rummage through all the underwater images from the coral reef that my son took when he went scuba-diving, in the vain hope I might find one.

I was in luck! I discovered a “school of Irukandji”, if that is the correct collective noun to describe a gang of these things, swimming right there in the reef…..


A Flock of Irukandji

Yeah, okay, it’s my thumbnail. It’s a silly joke. But unfortunately this tiny creature is serious trouble and certainly no joking matter. The Irukandji can be found in the northern waters of Australia, from Broome all the way round to Fraser Island. Just lately, the Irukandji has hit the news quite regularly….

  • Since Christmas, ten people have been rushed to Broome Hospital’s emergency department suffering from the potentially deadly sting.
  • ‘World’s best job’ man, Ben Southall, who won the job of caretaker on one of Australia’s tropical islands, was stung by the tiny, lethal jellyfish.
  • A 45-year-old Filipino man was stung by an Irukandji jellyfish when he was splashed with seawater while fishing, 25 metres ABOVE the water, from a bulk carrier off north Queensland.
  • Irukandji stings are on the increase. From what I have read, I would guess there are easily in excess of 100 Irukandji stings in Australian waters each year.
  • The Irukandji is heading south! Just last night on the news, Irukandji expert Dr Jamie Seymour said he would be absolutely shocked if the Irukandji were not at the Sunshine Coast within 5 to 10 years. Oh no! That’s our favourite beach and only an hour or so north of Brisbane.

This really is an Australian Bad Thing, being more venomous than the box jellyfish, and some say it is potentially a bigger threat than the shark. I am not so sure about that because the Irukandji does have a couple of “redeeming features” which do not apply to the other two.

  • Although there is no antivenom, there have been successful results with magnesium infusions, an established, safe and inexpensive treatment, in controlling the jellyfish’s lethal venom.
  • If the two deaths so far are typical, then it takes a long time for Irukandji Syndrome to kill. The first death took 30 hours and the second victim was in a coma for two weeks before losing his battle against the sting.

On the other hand, the box jellyfish and the shark can both kill in minutes, or even seconds in the case of the shark. Magnesium infusions are of no use to shark attack victims either.

The Irukandji, for the above reasons, will probably not claim many lives, almost 8 years have already passed since the last deaths. But they sure are going to be a big pain.

Despite all of the bad news, please remember that being stung by one of these jellyfish is still very rare. And for some people, like me, almost impossible.

I use the swimming pool. Here’s more about the Irukandji…

Hmm, if that last sentence is true, maybe it’s not the most venomous creature in the world after all.

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{ 12 comments… add one }
  • jake January 10, 2017, 10:59 am |

    crazy, that little thing can cause so much pain. after reading this, i did a search, found this video of an irukandji victim getting hit with a sudden wave of intense pain. its amazing how one second she’s talking normally, and ten seconds later, shes writhing around and moaning in agony.

    • BobinOz January 12, 2017, 12:32 am |

      The pain from the sting of an irukandji is, apparently, a 9/10. They also say there’s almost nothing much that can stop that wave of pain; it laughs at morphine. Victims just have to ride it through and that is clearly what this poor woman has had to do. Not very pleasant at all.

  • James March 8, 2012, 9:29 am |

    Hi Bob
    I have fond memories of my Irukanji sting on honeymoon in 2004 on cable beach, Broome. The swine got me in the armpit and really began to smart so I retreated to the shore. Sitting drying off feeling the intensity build and then the tingling down my arm was fun. the double vision became slightly disconcerting especially when the activity around the lifeguard further down the beach resulted in the”2″ ambulances arriving for a “pair” of swimmers. The beach was then closed so i headed over to see a jar full of what had stung me. fortunately the symptoms were fading as I learned about the nasty jelly. I retreated to the hotel for a nice cold anti-venom!
    I guess I was lucky, I got in the water that day. The day before we arrived at the beach to find it already closed by a 20foot salty swimming about 50yards out!
    Protective suit in the wardrobe waiting for my return to Oz!

    • BobinOz March 10, 2012, 12:03 am |

      Fond memories!! Do you also reminisce about visits to the dentist and the time you ran over your foot with the lawnmower?

      Sounds like you were very lucky. No need for hospital treatment? By cold antivenom do you mean ice, because I don’t think there is any kind of treatment for an Irukandji sting, is there? Other than pain relief that is.

      Glad you are still alive, it could have turned out differently.

  • Dr. Lisa-ann Gershwin June 15, 2010, 1:05 am |

    As a person who works with jellyfish, I have always preferred the collective terms “swarm” or “bloom”. In fact, I feel the urge to smack people who call them a smack, because it sounds so bloody rediculous!

    On a more serious note, the finer mesh nets have been in development for longer than I’ve been on the scene (12 years this July!), and they have the fiddly problem of becoming clogged with debris and growth too quickly to be useful in any practical sense (everytime you take them in and out, you run the risk of getting a jellyfish caught inside).

    And yes, Irukandjis are cubozoans (called ‘box jellyfish’ by the rest of the world), but in Australia, the ‘box jellyfish’ refers specifically to the species Chironex fleckeri (the so called “deadly box jellyfish’) — it’s one of those pesky issues of common names, and why Linnaeus cleverly developed binomial nomenclature. Sorry, I digressed… Yes, cubozoans… same class, different orders, different venoms, different ecologies, different biologies… probably more distantly related than birds and frogs, as far as how long they have been evolutionarily diverging.

    Townsville is by no means the only place with a pool — Airlie, Cairns, and Darwin have them too — but y’know, people just really want to go into the sea, to bond with the ocean with that serenity and carefree freedom that they see in the advertisements. Protective clothing makes a huge difference in terms of prevention — the Whitsundays region has been proactively emphasising the use of protective clothing for the past few years, and has steadily reduced sting-related hospitalisations over 90% from what they were before they got serious about protective clothing. Other regions still emphasise it to varying degrees, and have corresponding rates of stings. As a researcher, I can hold my hand to my heart and state that the only times I’ve been stung were either when I was testing something, or when I was stupid, but never through proper PPE (e.g., lycra or neoprene).

    As far as driving them extinct, good luck with that. A better and probably more productive use of effort would be the dengue mosquito….

    • BobinOz June 18, 2010, 1:50 pm |

      Hello Doctor

      Thanks for popping by and sharing your knowledge. Until now, everything I’ve learned about jellyfish has come from either Google, the National Geographic or the Animal Channel. So it’s nice to hear from an expert.

      Yes, driving them to extinction is a bit of a wish rather than an expectation. I can only see the problem getting worse. And you’re right, for many people the swimming pool just isn’t the same.

      So it looks like we all have to wear that fancy Lycra clothing. I’m the kind of guy who likes to wear something baggy, it kind of suits my shape. The idea of me going to the beach with a full body hugging suit which excentuates my every curve is probably worse than actually getting stung.

      I recently laughed off a redback bite, so perhaps I’m ready for the next stage? Sounds like you’ve been stung before, how bad was it?

  • BobinOz May 27, 2010, 4:56 pm |

    Yes, I think these pools by the beach may become more popular and will slowly head south. But they’re not much use to our surfer dudes, so they may have to suit up. Perhaps we will all end up wearing some kind of light but very loudly coloured full body swimwear.

    I didn’t think they were related to the box jelly, but some websites suggest they are, so maybe.

  • Monique May 26, 2010, 10:13 pm |

    Apart from swimming wearing pantyhose or a stinger suit jellyfish are’t something that can be stopped with a net, especially not ones that are so small. Australia’s answer to this would be saltwater pools by the beach, I know for certain Townsville does this and they can’t be the only ones with the idea.

    Also I was under the impressio Irukandji were a species of box jelly??

  • Emmanuel January 16, 2010, 12:50 am |

    One more thing: Groups of jellyfish are called a bloom or swarm.

  • Emmanuel January 16, 2010, 12:28 am |

    These are one example of animals I don’t mind driving to extinction. But on topic, aren’t there some kind of nets they could use at the beaches small enough to keep those jellyfish out of the swimming areas?

    • BobinOz January 17, 2010, 5:43 pm |

      According to the University of California Golf Club???? Who came top in Google for a search on “collective nouns list” a gathering of jellyfish is called a smack or a fluther. They didn’t list a bloom of anything but they had a swarm of rats. And, of course, a school of whales.

      On the other hand, plenty of people agree with you that it is a bloom or a swarm. Bloom makes sense because jellyfish actually grow like flowers. A seed falls on the seabed, grows into a plant, the plant grows “leaves” and when these leaves “fall”, or rather detach and float, they are jellyfish. Frightening really.

      Either way, smack, fluther, swarm or bloom, I couldn’t agree more with you. This is one creature that would be best if they could be described as extinct.

      I’m sure the Australians will come up with some kind of safety enclosure, but I’m not sure what it would be. Any net with a fine enough mesh to keep these little things out would probably be easily torn open by a bigger fish. Perhaps some kind of metal mesh?

  • Aviram January 13, 2010, 7:56 pm |

    “to describe a gang of these things”


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