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Portuguese Man-of-War

Page history last edited by David Deck 9 years, 2 months ago

Portuguese Man-of-War

David Deckelbaum

     A Portuguese Man-of-War, also know as a Bluebottle, is a jellyfish-like creature. Despite what its appearance is on the outside, it is not a jellyfish but a siphonophore which makes is different compared to the jellyfish which isn't actually one single organism. The Man-of-War is actually a colonial organism which means that it is made up of numerous organisms of the same species living very close together. These individuals are called zooids. Zooids are very similar to many other solitary animals but they are attached to each other and working together. It is a member of the Physalia family and lives it the surface of the ocean. They are translucent and mostly blue or purple. Its airbag which is also known as the pneumatophore floats on the surface while its tentacles which, are extremely poisonous float below the surface and can grow up to 165ft long. 










     The Man-of-War floats mostly throughout the ocean's warm waters (near the Equator). However, they cannot dictate the direction in which they are going; currents and the wind decide where they are going; because of this they can be found as far North as the Bay of Fundy for example.To stay safe from predators, they can deflate their airbags to submerge for a very short period of time. They live in groups of 1000 or more  They are eaten by mostly Loggerhead Sea Turtle and leatherback sea turtle as well as the sand crab. 

Prey Adaptations

     The Man O'War is loaded with numerous stinging cells which are called nematocysts. These cells contain a coiled tube that is tipped with "spikes" which are called barbs. If any pressure happens to be applied on the cells, the cells will release these barbs, almost acting like small arrows attacking whatever is applying the pressure. However, these arrows will stay attached to the Man O'War's tentacles as well. These "arrows" contain a vigorous poison similar to cobra venom. Any stung fish will die briskly. Yet, these tentacles do not harm the Loggerhead Sea Turtle, Leatherback Sea Turtle and Sand Crab as stated above.


Predator Adaptations

     Although they are mostly transparent as stated above, their tentacles resemble larval fish, copepods and small shrimp thus luring prey into their stinging net. Due to the absence of jaws and the lack of strength, its tentacles serve as a utility to stun and entangle its prey. Once they have trapped their prey, the Man-of-War contracts its tentacles to bring the prey to its secret digestive enzymes called polyps; what this does is liquefy their victim.




     The small fish called the Nomeus Gronovii is resistant to the Man-of-War's poison which is produced by its stinging cells. These small fish can also live among the tentacles. Although, they do tend to avoid the larger tentacles. But, they stay close to the smaller tentacles beneath the gas bladder because this is their main source of nourishment. The Portuguese Man-of-War can be often found with the Yellow Jack, the Clownfish, etc.


Comparison: Jellyfish



  • The Man-of-War and the Jellyfish have a very similar outward appearance. 
  • Both specimens have tentacles that contain stinging cells on them.
  • Jellyfish and Portuguese Man-of-Wars can live together in the same habitat. 



  • Man-of-War's tentacles can grow longer than Jellyfish's tentacles.
  • Jellyfish can dictate in which direction they are going.
  • Jellyfish swim underwater compared to the Man-of-War which floats on the surface of the water. 







Jellyfish. PhotographEncyclopaedia Britannica Image Quest. Tue. 4 June.  http://quest.eb.com/images/132_1317693?subjectId=0&collectionId=0&keyword=Jellyfish&localizeMetaData=false


Portuguese man-of-war. Photograph. Encyclopaedia Britannica Image Quest. Tue. 4 June. http://quest.eb.com/images/132_1316667?subjectId=0&collectionId=0&keyword=Portuguese+Man-of-war&localizeMetaData=false


portuguese man-of-war, physalia physalis. Photograph. Encyclopaedia Britannica Image Quest. Tue. 4 June. http://quest.eb.com/images/130_572430?subjectId=0&collectionId=0&keyword=Portuguese+Man-of-war&localizeMetaData=false


Portuguese Man-of-War. Enchanted Learning. 2000. Mon. 27 May. http://www.enchantedlearning.com/subjects/invertebrates/jellyfish/Manofwar.shtml


Portuguese man o' war. Wikipedia. May 31, 2013. Tue. 21 May. http://en.wikipedia.org/wiki/Portuguese_man_o'_war


The Cephalopods Page. Portuguese Man-of-War by Miranda Hoover. Feb. 24, 2004. Tue. 4 June. http://www.thecephalopodpage.org/MarineInvertebrateZoology/Physaliaphysalis.html


National Geographic. Portuguese Man-of-War. Wed. 22 May. http://animals.nationalgeographic.com/animals/invertebrates/portuguese-man-of-war/


Lady Wild Life. Portuguese Man-of-War. Nov 5, 2012.  Wed. 29 May. http://ladywildlife.com/viewmainpageinfo.php?pid=portuguesemanofwar
















Comments (2)

Dakota Albino said

at 7:25 pm on May 29, 2013


David Deck said

at 7:32 pm on May 29, 2013


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