Jellyfish are wonderfully simple organisms, and their shapes are beautifully compelling. Though fascinating to watch and fantastic to photograph, many jellies are venomous – some express mild venom that causes nothing worse than an itchy rash; others are deadly to humans. Here, we’ll take a comparative look at two of the world’s deadliest jellyfish species.
The World’s Most Venomous Creature
The Irukandji Jellyfish has venom 100 times more powerful than a cobra’s and a stunning 1,000 times more deadly than a tarantula’s. In fact, it is believed to be the most venomous creature on the planet.
These tiny jellyfish are found primarily throughout the waters off Northern Australia, though they’ve also been discovered off the Florida coast, throughout the British Isles, and even off the coast of Japan. Their bellpiece is typically between 5 and 25 millimeters across, and their stingers can be as short as just a few centimeters or as long as a meter.
While scientists have yet to learn much about the Irukandji’s life cycle, it is known that these jellyfish differ from other related species in that they have the unique ability to fire poisonous stingers from their tentacle tips and bellpieces in order to inject their prey with venom for quick debilitation and simple consumption.
When a human comes into contact with Irukandji venom, the result is Irukandji Syndrome, which includes severe pain, excruciating cramping in the muscles of the arms and legs, headaches, nausea, vomiting, increased blood pressure and elevated heart rate, and a psychological phenomenon marked by an inescapable feeling of impending doom. Victims typically require hospitalization, and symptoms can persist for anywhere from a few hours to as long as several weeks. An Irukandji sting can be fatal, though most victims survive thanks to medical intervention.
A Faster Killer
While the Irukandji is the most poisonous jellyfish known to humanity, the box jellyfish is actually a much larger threat to mankind. With an Irukandji sting, symptoms take long enough to manifest that it’s normally possible to treat an affected victim; a box jellyfish sting can result in death within just a few short minutes – even if the victim is a healthy, average-size adult human.
As the species name suggests, box jellyfish are somewhat cube-shaped. They have extremely potent venom. Often referred to as sea wasps or marine stingers, box jellyfish are capable of moving faster than other jellyfish species. In addition, these jellyfish possess a more developed nervous system than other jellyfish species do; they are even equipped with 24 eyes, and they are capable of fast, directional swimming as well as with obstacle avoidance and even a limited ability to learn and process information.
Box jellyfish are much larger than Irukandji; they can weigh in at as much as two kilograms, and their tentacles can reach a length of about three meters.
Venomous box jellyfish cause multiple deaths annually, particularly in the Philippines; in other warm climates, jellyfish exclusion nets have been set up at swimming beaches to prevent accidents.
Needless to say, it’s a good idea to avoid contact with jellyfish, as even non-poisonous species can cause skin irritation. If you are stung, you’ll find that vinegar can provide some relief, but only if nematocysts have not burst. If you believe you have come into contact with a deadly jellyfish, seek treatment immediately.