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Interesting Facts about Portuguese Man o' War

Sucheta Pradhan
The Portuguese man o' war is a colorful, jellyfish-like marine creature that is extremely venomous. Here are a few facts about this beautiful stinger.

It's really dangerous!

The sting of the Portuguese man o' war is active even several hours after its death. It can still cause considerable harm to animals as well as humans.
The Portuguese man o' war is a superorganism that dwells in the marine environment. The term superorganism essentially refers to a group or a colony of individual organisms which come together and function as one organic entity.
The creature's name has been derived from the 18th century Portuguese armed sailing vessel of the same name, which it supposedly resembles. The creature is oft seen floating on the surface of the ocean, and looks very similar to a jellyfish.
In fact, people who are unaware and unfamiliar with the creature itself and/or its biology, are very likely to think of it as a jellyfish, however, such is not the case. The most important difference between the two lies in the very structure of both the organisms.
The jellyfish is a singular, independent entity that can fulfill all its basic functions of moving, feeding, and reproduction on its own. On the contrary, the Portuguese man o' war is a colony of several different polyps (a zoological term for cylindrical, elongated creatures which cannot survive on their own), each of which has a specific function.

Portuguese Man o' War Facts

The Portuguese man o' war , Physalia physalis, is a cnidarian, also known as 'blue bubble' or 'bluebottle'. Cnidaria is a phylum of more than 10,000 marine species, which have special cells called cnidocytes, used for capturing prey.

Description and Habitat

➠ The creature is translucent and bears a slight tinge of purple, blue, pink or mauve shades.
➠ The Portuguese man o' war is generally found in warm waters around Australia and Hawaii. It floats on the water, and is often washed close to the shore, especially at the time of storms.


➠ It is composed of four different types of polyps, each of which perform a different function for the organism. The uppermost polyp that can be seen floating on water, is a bladder, filled with gas. This pneumatophore, more commonly known as the sail of the bluebottle, is a bilaterally symmetrical polyp that enables it to float.
➠ The Portuguese man o' war produces carbon monoxide, a poisonous gas that fills as much as 13% of the pneumatophore. The other gases include oxygen, nitrogen, and argon. Sometimes, traces of carbon dioxide are also present.
➠ Though the sail is always kept inflated, so that the bluebottle can float on water, in case of emergencies, such as a surface attack, the man o' war has an ability to deflate its sail, so that it can submerge itself under water for a little while.
➠ The second polyp, called dactylozooid is meant to act as a defense mechanism. It is elongated in shape, often also vermiform, and has one tentacle, but no mouth.
➠ The third polyp is the gonozooid that helps in the process of reproduction. Reproduction in case of the Portuguese man o' war happens by mitotic division - splitting of a mother cell into two individual daughter cells. These cells are present in the third polyp.
➠ The Portuguese man o' wars can reproduce and multiply so quickly that many times, warm water surfaces are covered by swarms of them.
➠ The fourth and the last polyp is the gastrozooid and it aids in feeding. The dactylozooids and gastrozooids work in conjunction with each other. Each tentacle of the dactylozooids possesses specialized contractile cells, the function of which is to drag the prey into the range of the gastrozooids. The gastrozooids then, secrete certain enzymes and aid in the process of digestion.

Venom and Diet

➠ The creature is carnivorous in nature, much like the other cnidarians, and is notably, very venomous. What seems like a transparent bottle, floating on water, has a number of tentacles hanging beneath its sail.
➠ These tentacles may grow as long as 10 meters, however, more often than not, they tend to be much shorter. Each tentacle has hundreds of stinging cells that can inject a very strong toxic substance, and instantly paralyze the prey.
➠ The venom of the Portuguese man o' war is contained in the nematocysts, which are thread-like, coiled structures used to sting and kill small marine inhabitants.
➠ While its venom is very strong and many times, fatal for numerous small marine species, it does not tend to be very toxic for humans. However, if the creature happens to sting a human, it can result in excruciating pain.
➠ The man o' war only feeds on those marine animals, which are paralyzed by its tentacles. This includes small fish, shrimp, marine plankton, etc.


➠ There are a number of creatures, which are immune to the sting of the Portuguese man o' war. The most interesting of these is the blanket octopus whose young ones carry broken tentacles of the Man o' war, probably to defend themselves from predators.
➠ The loggerhead turtle is also immune to the sting of the Portuguese man o' war. Its skin is so thick that the sting cannot penetrate. In fact, the loggerhead turtle feeds on the Portuguese man o' war.
➠ The sea slug, Glaucus atlanticus, also has the Portuguese man o' war as its main food, and so does the common purple snail, Janthina janthina, and obviously both of them are also immune to the venom.
➠ One of the most interesting predators is the man o' war fish, a small species of fish (Nomeus gronovii). It is partially immune to the venom of the Portuguese man o' war and lives among its tentacles. It also tends to eat the smaller tentacles, located directly underneath the pneumatophore. However, the fish is also sometimes, eaten by the creature.
➠ Some other fish like the clownfish and the yellow jack also choose to live among the tentacles of the Portuguese man o' war. Swimming among the tentacles of the creature, helps these fish to protect themselves from possible dangers, while it also helps the man o' war to attract its prey.
The Portuguese man o' wars are, more often than not, found in groups of approximately 1,000 or even more, floating on water. They are not equipped with any independent means of propulsion/locomotion. Owing to this, they either drift on the currents or move in the direction of the wind.