Sea Wasp: Extremely Venomous Jellyfish

Chironex fleckeri (Sea Wasp Jellyfish) is considered the most venomous animal on the planet. A single specimen of this jellyfish contains enough venom to kill up to 600 people. Since 1954, it is estimated that these jellyfish have been responsible for over 5,500 deaths.

If you ever wondered which is the most dangerous jellyfish in the world and want to know more. In that case, we will give you the answer through this article in which we talk about the sea wasp, its characteristics, where it lives, what it eats, and its sting.

Characteristics of the Sea Wasp

These are the main characteristics of the sea wasp jellyfish:

  • It is considered one of the most poisonous and deadly creatures on the planet.
  • Other names given to it include, box jellyfish, cubomedusa, and cubozoa jellyfish.
  • These names are given because of the square shape of the body that characterizes it, from where the 60 tentacles that it has are about 80 centimeters long and can reach up to 3 meters in length in the adult phase.
  • Sea wasp sizes vary between 10 and 20 centimeters, not counting the tentacles, and can reach a size similar to that of a basketball. They are also characterized by a light blue shade, are translucent, and glow in the dark.
  • Their life expectancy is relatively short, ranging from three months to half a year.
  • One of the sea wasp extraordinary differences from other jellyfish is that they have four sets of 20 eyes, while most jellyfish are blind. However, it is not yet known whether they see through them. This large number of eyes, and the many sensory organs they have, compensate for their lack of a brain.

Where the Sea Wasp Lives

After knowing some of its most important characteristics, another question that usually jumps out at us is where is the sea wasp to be found.

Sea wasps mainly inhabit tropical waters of Northern Australia, generally shifting towards the coast due to marine currents. They cohabit with one of their relatives, the Irukandji (Carukia barnesi), a diminutive jellyfish of the same type as the Box Jellyfish. The Irukandji Jellyfish is known to cause the Irukandji syndrome. The Irukandji syndrome is a rare disease first detected in 1922.

Irukandji syndrome causes:

  • severe pains
  • tachycardia
  • nausea
  • sweating and hypertension

The box jellyfish also inhabits the entire Indian and the Pacific Ocean. However, specimens have also been detected in areas of New Guinea, Vietnam, and the Philippines. Although the sea wasp has a wide geographic distribution and can travel great distances, in general, adults tend to remain in small, restricted areas. Even so, the presence of this jellyfish in other parts of the ocean is still being studied.

Also, during October and May, sea wasps approach the coasts to reproduce. Due to this event, in many places such as Queensland in northwestern Australia, swimming is prohibited during this period.

What the Sea Wasp Eats

Like the rest of the jellyfish, sea wasps feed on plankton and small marine animals. In general, their feeding is limited to what they can find since they do not hunt and therefore do not look for food. Sometimes, besides eating plankton, they eat smaller jellyfish, so they become predators of other jellyfish species. Through their stinging tentacles, these jellyfish manage to catch and kill their prey quickly.

As for the predators of the sea waspthe green sea turtle (Chelonia mydas) can feed on sea wasps. The green sea turtle has thick skin that prevents them from being severely stung by this dangerous species.

Poison and Sting

Along their tentacles, sea wasps have millions of microscopic hooks, called cnidocytes, filled with venom inside. A single sting results in skin necrosis and extreme pain.

Also, this venom contains a complex mixture of proteins and toxins that are:

  • myotoxic
  • hemolytic
  • dermonecrotic and lethal

As they attack the:

  • heart
  • nervous system
  • respiratory system
  • the skin and muscle cells in the area that receives the sting

In humans, they can cause death from cardiac arrest or paralysis from pain in a matter of minutes. The pain caused by even the slightest contact with the jellyfish is so intense that it can cause the victim to go into shock.

Concerning other jellyfish, it has been determined that the pain caused by sea wasp venom is at least ten times more powerful than that of the Portuguese man o’ war (Physalia physalis). It is also at least several orders of magnitude more powerful than that of the sea nettle (Chrysaora quinquecirrha).

Venom Antidote

Researchers at the University of Sydney in Australia discovered an antidote to the sea wasp sting.


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