10 Venomous Irukandji jellyfish Facts

One of the smallest creatures in the ocean is also one of the most dangerous animals in Australia. Being stung by this particular type of jellyfish causes a syndrome that could potentially have lethal consequences.

Let’s take a closer look at some of the most interesting facts about the Irukandji Jellyfish, one of the most intriguing, yet dangerous types of jellyfish on the planet.

1. They can be found in the waters of northern Australia

The Irukandji jellyfish is a very small type of box jellyfish that is extremely venomous. It’s found in the waters in northern Australia, more specifically off the coast of Queensland in the northeastern part of the country.

While the range was originally established as the region north of Cairns, this has been gradually moving south, with sightings as far as the area of Rockhampton not being uncommon these days.

Irukandji Jellyfish facts
The peculiar creature in the ocean / Wiki Commons

2. It was named after the aboriginal people who live here

This type of jellyfish was named after the indigenous Australian people who live in this part of Australia, the Irukandji People, also known as the “Yirrganydji.”

They originally inhabited a relatively small region in Queensland between Cairns and Port Douglas. Because of the proximity to the ocean and river mouths, these were fishermen who lived from the sea.

3. There are 16 different species of this type of jellyfish

The Irukandji jellyfish consists partly of the genus “malo,” a genus of box jellyfish which consists of 4 different species. Another genus is the “Carukia” which features 2 species of this type of jellyfish.

There are a total of 16 known species of Irukandji jellyfish of which the Carukia barnesi, Malo kingi, Malo maxima, Malo Filipina, and Malo bella are the most famous.

Most of these species look pretty much the same, and the Carukia barnesi and Malo kingi and virtually indistinguishable from each other.

Malo Barnesi Irukandji Jellyfish
Carukia barnesi / Wiki Commons

4. They are barely noticeable in the ocean due to their small size

One of the main reasons why most species of Irukandji jellyfish are indistinguishable from each other is because they are extremely small. Most species never grow bigger than between 5 millimeters (0.20 inches) and 25 millimeters (0.98 inches).

A mature Carnukia barnesi grows anywhere between 12 and 30 millimeters (0.47 and 1.18 inches) and they are soft-bodied and feature 4 relatively long tentacles compared to their body size.

These tentacles can reach a length of anywhere between 1 centimeters to 1 meter (3.3 feet) in length.

5. Their sting causes a specific syndrome with the same name

It’s the tentacles that feature stingers that allow these remarkable creatures to cause serious trouble. The sting of these jellyfish starts as an irritating feeling and gradually evolves into excruciating pain.

The symptoms start about 30 minutes after exposure and last anywhere from 4 to 30 hours but can potentially last up to 2 weeks in rare cases.

The syndrome caused by the sting of the Irukandji jellyfish is called the Irukandji Symptom, a name given to it in 1952 by Australian toxicologist Hugo Flecker.

Unfortunately, nearly all stings require hospitalization as they are potentially lethal. In the worst case, the Irukandji syndrome results in hypertension, an enlarged heart, pulmonary edema, and even cardiac arrest.

Irukandji jellyfish fun facts
The small jellyfish / Gondwana Girl / https://creativecommons.org/licenses/by-sa/3.0/deed.en

More interesting facts about the Irukandji Jellyfish

6. One of the species of Irukandji jellyfish known as “Malo kingi” or the “common kingslayer” was named after the only known casualty caused by its sting.

An American tourist named Robert King was stung while he was snorkeling off the coast of Queensland in 2002 and died as a result of sting-induced hypertension. He remains the only known victim of this species.

7. Even though Robert King is the only known victim of the species now known as the malo kingi, he is far from the only victim who passed away after being stung by the Irukandji jellyfish.

The Irukandji syndrome has made at least 70 known victims and the number of stings is rising every year as well as the range of this creature extends further south.

8. Even though all species of Irukandji jellyfish are extremely venomous, this only applies to mature individuals. Juveniles have been demonstrated to possess a much lower level of toxicity.

One of the potential reasons for this is the absence of halo-rings around their tentacles. Regardless, very little is known about both the lifecycle of these creatures and the venom they produce.

Marine Stinger Chart Irukandji Jellyfish
Marine stinger chart in Queensland / Brewbooks / https://creativecommons.org/licenses/by-sa/2.0/

9. The symptoms of a sting from these extremely venomous jellyfish include severe headache, backache, muscle pains, chest and abdominal pain, nausea and vomiting, sweating, and anxiety. 50 to 100 people are admitted to Australian hospitals every year.

Unfortunately, no antivenom exists as of today and the initial feeling of the sting has been described as feeling a bit similar to a mosquito bite. hen treated properly, however, a single sting is nearly never fatal.

10. Something that emphasizes the potent of the toxins injected by the Irukandji jellyfish is a comment made by Australian writer Robert Drewe. He describes the sting as being:

100 times as potent as that of a cobra and 1,000 times stronger than a tarantula’s.

Even though this statement might be a bit exaggerated, perhaps taking a dip in the waters off the coast of Queensland isn’t the best idea, don’t you think?

Luckily, something referred to as a “jellyfish net” has been invented following the death of Mr. King and these can be found in various placing along the QLD coast. These are 100% jellyfish-proof and keep you safe and sound while enjoying a swim!

Jellyfish net queensland