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Portuguese Man-Of-War

The Portuguese man-of-war is a creature that prefers the warmer waters of the open Atlantic. However, it can happen to be driven inshore by strong oceanic winds, which is why it is seen along the North Atlantic coasts of the Americas, Europe and Africa. Some species live in the Mediterranean.

The sting from one of these creatures is not strong enough to kill a human, but can cause severe pain for several days. Not much really! But the Portuguese man-of-war is not just one living organism: it is a colony made up of many individual organisms, each one having a different function.

It relies on its gas-filled float (this is the part above the water), to catch the winds and water currents, and carry it far across the open oceans.

The Portuguese Man-of-War has a very complex lifestyle even though it is conglomeration of simple organisms. It exists in two different forms: one as a floating colony of polyps (organisms), and another as a tiny, free-swimming, disc-shaped ‘medusa’. The Medusa is developed like a bud on one of the reproductive polyps which hang from the gas-filled float. At a certain time, the tiny bud then breaks of from the ‘mother’ and swims free, just like a tiny jelly-fish.
By the time the medusa (or bud) has broken off, it is sexually mature. It can produce sperm and eggs; the fertilised eggs develop into floating larvae. Each larvae is a single polyp, but in time it produces more polyps by ‘budding’; similar to the way a daffodil multiplies by producing more bulbs.
Each polyp produces more polyps, eventually makes a complete Portuguese Man-of-War.

The oceanic Portuguese man-of-war is not an endangered species at present. Because it uses to whole of the ocean as its home it is fairly safe from habitat loss and the pollution that affects coastal animals. But one risk is from floating oil from tanker spillages. Another ‘threat’ is strong winds that blow it onto Atlantic shores. Stranded jelly-fish break up and eventually dry up.

The Portuguese has no brain (no jokes please!) to control its behaviour. It is made up of network fibres that mechanically react to stimuli. As the Portuguese man-of-war floats along the prey that gets caught within its tentacles. This is the response needed to ignite the stinging cells and trigger the muscular contractions that allow prey to be captured, taken up, and eaten.

The name ‘Portuguese Man-Of-War’ comes from the similarity to the hats worn by medieval Portuguese sailors.

Tentacle length can vary from 10m to up to 60m.

Number of Young: Millions over one lifetime.

Lifespan: unknown