Box Jellyfish Sting Box Jellyfish Tentacles, Sting & Survival

Photo: Box jellyfish with tentacles.

Photo: Box jellyfish with venomous tentacles near a swimmer

The box jellyfish is a cube-shaped sea jelly with up to fifteen slender, 4.5 meter long tentacles with excruciatingly painful stings that can kill a human in minutes. In Australia, box jellyfish have caused at least 79 deaths since 1883. The most recent was a 17-year boy who died in 2021.

The box jellyfish is not aggressive towards humans. Unfortunately, this jellyfish enjoys the warm shallow waters with slightly sloping coastlines that are also popular with people. Because it is almost transparent, it is very difficult to see in the water. In most instances, a swimmer only becomes aware of it once they have been entangled in the jellyfish's tentacles and been stung.

It should be noted that the box jellyfish is venomous not poisonous. This is because a venomous animal, such as the box jellyfish, injects its toxins into another animal. While a poisonous animal's entire body or parts of it may contain toxic substances that are harmful if touched or eaten. Because the box jellyfish injects its toxins, it is venomous.

Photo: Diagram of cnidocil, nematocysts and barbs

The box jelly tentacles have hundreds of specialised hyper-sensitive stinging cells called nematocysts. When an object touches the surface of a nematocyst it fires a deadly razor-sharp barbs, attached to a thread, in less then a microsecond (thats one millionth of a second). These barbs either pierce the flesh or the threads ensnare its prey, releasing toxins into its victim paralysing, killing, or scaring it off in excruciating pain.

The toxin fired from the jellyfish's nematocysts attacks the heart, nervous system, and skin cells. The pain experienced by its victim is instantaneous and described like being "branded with red hot irons". The venom causes the victim's cells to become porous and leak potassium, causing hyperkalemia. This can lead to cardiovascular collapse and death within 2 to 5 minutes.

Survival from a box jellyfish sting depends on the amount of toxin injected into its victim and the speed at which detoxification occurs. Unfortunately, it is very unlikely that a person would survive a full-fledged attack because, in most instances, it is impossible to administer an antidote quickly enough.

The only remedy to date is vinegar, which prevents the discharge of any active neophytes still on the victim's skin and seems to neutralize the effect of the stings and relieve the pain. Since a cardiac arrest is like to occur very quickly, CPR must be administered until professional help arrives.

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Light-skinned People are More Likely to be Stung

Light-skinned people are more likely to be stung by a box jellyfish than dark-skinned people. This is because the eyes of a box jellyfish are more likely to see the dark contrast of a dark-skinned person in the water and realise that it is not pry and swim away. On the other hand, a light-skinned person is not as visible to the jellyfish and is more likely to come in contact with it.