chironex fleckeri & irukandji

Thank heavens for the Discovery Channel. After wrapping up EFR training today at the dive school, I was, for fairly obvious reasons, led to watch a show with an underwater focus. What I stumbled upon was Killer Jellyfish, a documentary about the box jellyfish in Australia’s Great Barrier Reef.

These box jellyfish, or chironex fleckeri, are amazing creatures, differing from their typical jellyfish counterparts in so many ways. These amazing invertebrates thrive in the warm waters of northern Australia, eating up to 1/4 their weight every day and touting the ability to out swim humans. They’re most prevalent in the height of the busy summer season, following their coral-like spawning. They are the size of a basketball and have up to 60 tentacles. With this powerful structure, they can swim, not needing the current, tides and wind like their traditional counterparts. One box jellyfish highlighted on the show swam 10 miles over a 24 hour period!

What’s most amazing, however, is their potency. They’re hundreds of times more potent than a cobra, 500 times more toxic than a Portuguese Man o’ War, and thousands of times more potent than a tarantula. The box jellyfish are by far the most advanced of the jellyfish.

The chironex fleckeri have primitive brains. Additionally, they can see, and see right way up no matter how they’re oriented. They have 24 eyes grouped in four clusters of six. Of the six eyes in each cluster, 2 are used to make the images, and the other four serve a purpose of only collecting light. Because of blurred vision, they sleep at night, unable to see obstacles or prey. To their advantage, their nighttime sleep allows them to conserve energy and rest.

Surprisingly, though, the chironex fleckeri is not the most potent form of box jellyfish. That title goes to the irukandji, the smallest of the box jellyfish. The irukandji have stinging cells on their bell, making them unlike other jellyfish. They have tentacles as fine as human hair; tentacles that are as vital as an arm. They’re one of the world’s most venomous creatures, and are merely the size of a human fingernail! These box jellyfish eject venom only from the tentacle tip, whereas the chironex release venom from points along the entire stinger. The stingers on the irukandji fire only once, but are constantly replaced. Frighteningly, this smallest box jellyfish can kill in just 1 to 2 minutes. Yes, 1 to 2 minutes!

What amazing creatures. Killer Jellyfish made me rethink my desire to someday dive on the Great Barrier Reef. Final decision? Nah – I won’t be giving that up!

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Note #1: Tomorrow’s excitement is Colossal Squid, airing on the Discovery Channel at 9 pm ET. If I remember to watch it, that’s next on my list!

Note #2: Go figure, the Promises Message in my Dove Chocolate was, “You cannot discover new oceans unless you have the courage to lose sight of the shore.” Baby, bring it on!

minski39September 3, 2008 - 1:26 am

Note: Colossal Squid was no where near as exciting as Killer Jellyfish. I did watch it, but feel there’s no need to review/summarize – it just wasn’t as cool! The only excitement came from the fact that these 30′, 1,000+ lb. mammoths are covered not in suckers but in up to 3″ long hooks that rotate 360 degrees! Ouch! They also feature eyeballs that have a diameter of 10″ – bigger than a soccer ball!

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