Sunday, 26 September 2010

Portuguese Man o' War

"Gosh" you might say, "that's one weird looking jellyfish". Well, you'd be partly right. Certainly it looks rather odd but it isn't a jellyfish, it isn't even one animal. The Portuguese Man o' War is in fact a whole colony of four different kinds of organism, each adapted to perform a specific function for the benefit of the whole.

They are all either a kind of polyp, which are like really small sea anemones, or medusae, similar to tiny jellyfish, but here they are all connected to each other and are unable to survive on their own. Such is the way of the siphonophores, an order of colonial creatures related to... can you believe it? Sea anemones and jellyfish. In case you were wondering, the whole thing develops from one egg that sprouts all the other parts, rather than loads of little polyps undertaking an epic journey of self discovery in search of their People.

It gets its name from the shape of its sail which resembles that of 16th century warships like man of wars and caravels. Or is it men of war? Men of wars? Whatever, said sail is our first organism, a pneumatophore which the man o' war fills with air to enable it to float in the open ocean. It get up to 30 centimetres long and about half that tall, it can be rolled in the water to keep it damp and it can even be deflated and allow submersion in case of predatory horrors from above. One really nice detail is that they can be left-handed or right-handed, so some sail right of the wind and others left. This means that if the wind takes some to an unseemly death on the beach, others will find that same wind takes them off somewhere else entirely. Clever stuff!

Image by nashworld via Flickr
The body beneath the pneumatophore is dominated by the feeding polyps which each have a single tentacle dangling beneath them. In other words, the Portuguese man o' war has thousands of terrifying, painful, deadly stinging tentacles that usually reach around 10 metres (30 feet) long but can occasionally reach as much as 22 metres or 70 feet in length. These things contain the family speciality: nematocytes. When an unwary fish gets too close, a tiny hair senses its presence and triggers a barbed tube to be fired at incredible speed and impale prey. It all happens in a few millionths of a second, and the unfortunate fish is immediately paralized by the injected poison. The polyp aren't finished yet, though.

They start to reel their load up toward our third organism, the gastrozooids. These have tiny but rather disgustingly flexible mouths that are only about 2 millimetres in diameter when at rest, but as food finally starts to reach their lofty heights they expand tenfold in anticipation, spread over the surface of their catch and begin the digestion process with an assortment of enzymes.


The final organism are the medusae used for reproduction, the gonozooids, which are hermaphrodite - each have both the male and female parts. I guess an individual Portuguese man o' war could therefore reproduce all on its own, although it isn't really necessary; the fact that they get around on currents and winds means that they are often found in groups that can number in the thousands.

Did I say groups? Maybe that should be armies! Or probably armadas. They are found in tropical and subtropical waters all over the world, military maneuvers off the coasts of Australia, New Zealand, Pakistan and within the Mediterranean Sea, amphibious assaults of Mexico, California, Florida, Hawaii, Costa Rica, South Africa and Guyana, scouts have even been sighted off the coast of Wales. Of course, this often results in death, but even a dead man o' war washed up on the beach can deliver a painful sting. A formidable force then, especially for something without a brain, but then it is a warship after all, with a crew of thousands.

.....

I don't want to get all 'existential crisis' on you but seriously, what do you see when you look in the mirror? An individual, with thoughts and feelings, dreams and intentions, love and belief. Or a huge colony of cells working together, each contributing with their own specialism for mutual benefit, living, dying and being replaced. A complex society in motion. It's an unsettling thought.

Ha! Maybe this answers it!

2 comments:

Robyn Graham said...

I was stung by one of these recently while swimming in Florida and wanted to learn more about them. Thanks for the interesting and informative post!

Comment1 said...

Glad I could help in your time of need! Hopefully you won't get bitten, stung or generally beaten up by too many of the monsters featured here.

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