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What are Sea Wasps?

Sea Wasps, a colloquial term for the lethal box jellyfish, are marine marvels with a sting that's among the most venomous on Earth. These translucent creatures, often found in Indo-Pacific waters, can turn a leisurely swim into a life-threatening encounter. Intrigued by how such beauty conceals danger? Discover the mysteries of Sea Wasps and their paradoxical existence in our oceans. What secrets do they hold?
Ken Black
Ken Black

Sea wasps, or box jellyfish, are invertebrates. They are named for their cube-shaped medusae, which is the main part of a jellyfish's body. Belonging to the class of animals called cubozoa, they are often referred to as cubozoans. Sea wasps are noted for their powerful and painful stings, which are very reminiscent of flying wasps, but with a notable exception. The sting of sea wasps can be fatal.

Sea wasps are best known for their venom, which is exhibited by a number of different species. These animals have a powerful toxin that is used to capture prey. However, on chance encounters with humans, they have also been known to produce serious medical situations. Sea wasps have been credited with causing a number of fatalities.

Some beach goers choose to wear pantyhose on their legs and arms to protect themselves from sea wasps.
Some beach goers choose to wear pantyhose on their legs and arms to protect themselves from sea wasps.

One species of sea wasp, known as Chironex fleckeri, is especially dangerous. Its venom is among the most powerful on Earth. The main body of the jellyfish can be the size of a basketball and it can have up to 60 tentacles hanging down as long as 15 feet.

Ounce for ounce, the Chironex fleckeri is perhaps the most venomous animal on the planet but it is not the only species that is capable of delivering a fatal blow. Some sea wasps, as small as a thumbnail, have delivered fatal stings. Therefore, extreme caution should be taken in areas where they are known to be.

Scientists know the sea wasps stings are triggered by a chemical reaction. They have been able to observe that pouring alcohol into water with sea wasps will trigger a release of their powerful toxins. Therefore, some have come up with a way of protecting themselves from the creatures using a barrier method.

Those going to the beach, especially in Australia where sea wasps are particularly bad, sometimes wear women's pantyhose on their legs and arms. Just this thin amount of fabric is enough to keep the sea wasps from releasing their toxins when coming into contact with people because it blocks the chemical reactions from taking place. While it may look strange, many feel that the benefits are worth the embarrassment.

In most cases, the sting of the box jellyfish does not cause death, but it always has the potential to do so. In fact, the jellyfish, even the most venomous, releases such a small amount of venom that it rarely causes death. However, each sting can be extremely painful and requires immediate medical attention. In the cases of the worst stings, antivenom may be applied.

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Discussion Comments


I'm hoping to take a trip to Australia and get in some diving, so the pantyhose tip is really useful, thanks.

Someone told me that if an Australian sea wasp attaches itself to you, neat vinegar will break the grip of the tentacles. That's not something I would usually carry to the beach but it's worth a try.


@Penzance356 - Vague memories of science class lead me to believe that sea wasps are linked to coral reefs in some way. There's very little on this planet that exists for no reason, though perhaps evolution has changed that to some extent.

Box jellyfish don't go looking for humans to sting, and most encounters are accidental on both sides. It could be said that we have no real right to be messing around in their territory, so we have to take the risk of being hurt by those who call the ocean their home.


I would love to know what purpose these creatures serve in the bigger picture of life on earth! They just seem to exist to cause harm to people, and the thought of meeting some kind of deadly jellyfish is enough to keep me out of the ocean, period!

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    • Some beach goers choose to wear pantyhose on their legs and arms to protect themselves from sea wasps.
      By: vladimirfloyd
      Some beach goers choose to wear pantyhose on their legs and arms to protect themselves from sea wasps.