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Wild Things: Portuguese Man-of-War

Dec 27, 2006

The Portuguese Man-of-War is a jelly-like marine animal but it's no jellyfish. In fact, these sea creatures are four different polyps that rely on each other to survive. Man-of-Wars are well known for their painful and powerful sting. They can be found in warm water all over the world.

This stinging animal is called the Man-of-War because it looks a bit like a Portuguese battleship with a sail. It's not built like a battle ship. The body is a gas filled float which can be blue to pink in color (it looks like a bag.) It can be anywhere from three to 12 inches (nine to 30 centimeters.) Underneath the float are clusters of polyps which coiled tentacles hang off of. The stinging tentacles can be up to 165 feet (about 50 meters) long. Sometimes the gas bag will flop over in the water but its muscles pull itself back up. The crest above the float is only a few inches tall and acts like a sail. It relies on the wind to move it from one place to another.

Since it has no control over where it goes Man-of-Wars are often found washed ashore, especially during winter and when the wind is bad. The bag that keeps it afloat must be kept wet. If the bag dries then the Man-of-War dies. To keep it from drying out the animal dips its sail in the water once every so often. When it's in the water, the Man-of-War uses the tentacles to capture small fish, plankton and crayfish. The tentacles paralyze prey. By contracting its muscles, the Man-of-War's tentacles can move fairly quickly.

The stings of the Man-of-War aren't just painful to their prey. It can cause some serious pain and effects to people too. This includes fever, shock as well as heart and lung problems. If you're stung by a Man-of-War pick off any visible tentacles, then rinse with fresh or salt water. Put ice on the area. Because you might go into shock it is important to get medical help as soon as possible. The toxins from tentacles are about 75 percent as powerful as cobra venom. Ouch! Even dead Man-of-Wars stranded on the beach can still sting so don't touch them and keep out of the water if they are present.

This is Interesting

  • Sometimes you can see Man-of-Wars floating along in groups of up to 1000 or more.
  • When the weather gets bad these guys know what to do. They can deflate their floats so that the weather will not harm it. After all, they are delicate.
  • The float, or bag, is filled with the rare gas Argon - no one knows why.

Have you had a run-in with a Man-of-War? Do you know anyone who has? Tell us about it.

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