Portuguese man o' war

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Portuguese man o' war
Scientific classification
Species:P. physalis
Binomial name
Physalia physalis
(Linnaeus, 1758)
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Portuguese man o' war
Scientific classification
Species:P. physalis
Binomial name
Physalia physalis
(Linnaeus, 1758)

The Portuguese man o' war (Physalia physalis), also known as the Portuguese man-of-war, man-of-war, or bluebottle, though often mistaken as a jellyfish, is a marine cnidarian of the family Physaliidae. Its venomous tentacles can deliver a painful sting.

Despite its outward appearance, the Portuguese man o' war is not a jellyfish but a siphonophore, which differs from jellyfish in that it is not actually a single multicellular organism but a colonial organism made up of many highly specialized minute individuals called zooids.[1] These zooids are attached to one another and physiologically integrated to the extent that they are incapable of independent survival.


The name "man o' war" comes from the man-of-war, an 18th-century armed sailing ship,[2] and the cnidarian's supposed resemblance to the Portuguese version at full sail.[3] (In other languages it is simply known as the 'Portuguese war-ship' (Dutch: Portugees Oorlogsschip, Finnish: Portugalinsotalaiva), the 'Portuguese galley' (German: Portugiesische Galeere, Hungarian: portugál gálya), or the 'Portuguese caravel' (Portuguese: "caravela portuguesa", Spanish: "carabela portuguesa", Italian: "caravella portoghese", Swedish: "Portugisisk örlogsman").

Habitat and location[edit]

The Portuguese man o' war lives at the surface of the ocean. The gas-filled bladder, or pneumatophore, remains at the surface, while the remainder is submerged.[4] Since the Portuguese man o' war has no means of propulsion, it is moved by a combination of winds, currents, and tides. Although it can be found anywhere in the open ocean (especially warm water seas), it is most commonly found in the tropical and subtropical regions of the Pacific, Indian and Atlantic oceans. The Portuguese man o' war has been found as far north as the Bay of Fundy and the Hebrides.[5]

Strong winds may drive them into bays or onto beaches. It is rare for only a single Portuguese man o' war to be found; often the finding of one results in the finding of many.[4] Attitudes to the presence of the Portuguese man o' war vary around the world. Given their sting, however, they must always be treated with caution, and the discovery of men o' war washed up on a beach may lead to the closure of the whole beach.[6]


Physalia physalis

The Portuguese man o' war is composed of four types of polyp.[4] One of the polyps, a gas-filled bladder called the pneumatophore (commonly known as the sail), enables the organism to float. This sail is bilaterally symmetrical, with the tentacles at one end, and is translucent, tinged blue, purple, pink, or mauve. It may be 9 to 30 centimetres (3.5 to 11.8 in) long and may extend as much as 15 centimetres (5.9 in) above the water. The Portuguese man o' war generates carbon monoxide in its gas gland, filling its gas bladder with up to 14% carbon monoxide. The remainder is nitrogen, oxygen and argon, atmospheric gases that diffuse into the gas bladder. Carbon dioxide occurs at trace levels.[7] The sail is equipped with a siphon. In the event of a surface attack, the sail can be deflated, allowing the organism to briefly submerge.[8]

The other three polyp types are known as dactylozooid (defence), gonozooid (reproduction), and gastrozooid (feeding).[9] These polyps are clustered. The dactylzooids make up the tentacles that are typically 10 metres (33 ft) in length but can be up to 50 metres (160 ft).[4] The long tentacles "fish" continuously through the water, and each tentacle bears stinging, venom-filled nematocysts (coiled, thread-like structures), which sting and kill small sea organisms such as small fish and shrimp. Contractile cells in each tentacle drag the prey into range of the digestive polyps, the gastrozooids, which surround and digest the food by secreting enzymes that break down proteins, carbohydrates and fats, while the gonozooids are responsible for reproduction.


This species and the smaller Indo-Pacific man o' war (Physalia utriculus) are responsible for up to 10,000 human stings in Australia each summer, particularly on the east coast, with some others occurring off the coast of South Australia and Western Australia.[10]

The stinging, venom-filled nematocysts[11] in the tentacles of the Portuguese man o' war can paralyze small fish and other prey. Detached tentacles and dead specimens (including those that wash up on shore) can sting just as painfully as the live organism in the water and may remain potent for hours or even days after the death of the organism or the detachment of the tentacle.[12]

Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last 2 or 3 days after the initial sting, though the pain should subside after about an hour. However, the venom can travel to the lymph nodes and may cause, depending on the amount of venom, a more intense pain.[citation needed] A sting may lead to an allergic reaction. There can also be serious effects, including fever, shock, and interference with heart and lung function. Stings may also cause death,[13] although this is extremely rare. Medical attention may be necessary, especially if pain persists or is intense, there is an extreme reaction, the rash worsens, a feeling of overall illness develops, a red streak develops between swollen lymph nodes and the sting, or either area becomes red, warm and tender.

Treatment of stings[edit]

Stings from a Portuguese man-of-war may result in a severe dermatitis.[14]:429[15] The Portuguese man o' war is often confused with jellyfish, which may lead to improper treatment of stings, as the venom differs from that of true jellyfish. Treatment for a Portuguese man o' war sting includes:

Vinegar is not recommended for treating stings.[17] Vinegar dousing increases toxin delivery and worsens symptoms of stings from the nematocysts of this species. Vinegar has also been confirmed to provoke hemorrhaging when used on the less severe stings of nematocysts of smaller species.[20]

Predators and prey[edit]

The Portuguese man o' war is a carnivore.[4] Using its venomous tentacles, a man o' war traps and paralyzes its prey. It typically feeds upon small marine organisms, such as fish and plankton.

Portuguese man o' war in Tayrona national park, Colombia

The loggerhead turtle feeds on the Portuguese man o' war, a common part of the loggerhead's diet.[21] The turtle's skin is too thick for the sting to penetrate.

The sea slug Glaucus atlanticus also feeds on the Portuguese man o' war,[22] as does the violet snail Janthina janthina.[23]

The blanket octopus is immune to the venom of the Portuguese man o' war; young individuals carry broken man o' war tentacles, presumably for offensive and/or defensive purposes.[24]

The ocean sunfish's primary diet consists of jellyfish, but it can also consume Portuguese men o' war.

Commensalism and symbiosis[edit]

A small fish, Nomeus gronovii (the man o' war fish or shepherd fish), is partially immune to the poison from the stinging cells and can live among the tentacles. It seems to avoid the larger, stinging tentacles, but feeds on the smaller tentacles beneath the gas bladder. The Portuguese man o' war is often found with a variety of other marine fish, including clownfish and yellow jack. The clownfish can swim among the tentacles with impunity, possibly owing to their mucus, which does not trigger the nematocysts.

All of these fish benefit from the shelter from predators provided by the stinging tentacles, and for the Portuguese man o' war the presence of these species may attract other fish to feed on.[25]


Portuguese man o' war in Miami, FL 
Portuguese men o' war washed ashore on Maroubra Beach, New South Wales, Australia 
Portuguese man o' war captured live in Mayaro Beach, Trinidad and Tobago 
Portuguese Man o' War at Palm Beach, FL 

See also[edit]


  1. ^ Grzimek, B., N. Schlager & D. Olendorf 2003. Grzimek's Animal Life Encyclopaedia. Thomson Gale.
  2. ^ Marine Science Textbook by Thomas F. Greene
  3. ^ David Millward (8 September 2012). "Surge in number of men o'war being washed up on beaches". The Daily Telegraph. Retrieved 8 September 2012. 
  4. ^ a b c d e Portuguese Man-of-War. National Geographic.
  5. ^ Halstead,B.W., Poisonous and Venomous Marine Animals of the World, 1988, Darwin Press
  6. ^ "Dangerous jellyfish wash up". BBC News. 2008-08-18. Retrieved 2011-09-07. /
  7. ^ Wittenberg, Jonathan B. (1960-01-12). "The Source of Carbon Monoxide in the Float of the Portuguese Man-of-War, Physalia Physalis L". Journal of Experimental Biology 37 (4): 698–705. ISSN 0022-0949. Retrieved 2013-02-12. 
  8. ^ Physalia physalis. "Portuguese Man-of-War Printable Page from National Geographic Animals". Animals.nationalgeographic.com. Retrieved 2009-12-07. 
  9. ^ "Aloha.com". Aloha.com. Retrieved 2011-09-08. 
  10. ^ Fenner, Peter J.; John A. Williamson (December 1996). "Worldwide deaths and severe envenomation from jellyfish stings". Medical Journal of Australia 165 (11–12): 658–661. ISSN 0025-729X. PMID 8985452. Retrieved 2009-09-04. "In Australia, particularly on the east coast, up to 10 000 stings occur each summer from the bluebottle (Physalia spp.) alone, with others also from the "hair jellyfish" (Cyanea) and "blubber" (Catostylus). More bluebottle stings occur in South Australia and Western Australia, as well as stings from a single-tentacled box jellyfish, the "jimble" (Carybdea rastoni)" 
  11. ^ 5. Yanagihara, A.A., Kuroiwa, J.M.Y., Oliver, L., and Kunkel, D.D. The ultrastructure of nematocysts from the fishing tentacle of the Hawaiian bluebottle, Physalia utriculus (Cnidaria, Hydrozoa, Siphonophora). Hydrobiologia 489, 139–150, 2002.
  12. ^ Auerbach, PS. (1997). "Envenomation from jellyfish and related species". J Emerg Nurs 23 (6): 555–565. doi:10.1016/S0099-1767(97)90269-5. PMID 9460392. 
  13. ^ Stein MR, Marraccini JV, Rothschild NE, Burnett JW. (1989). "Fatal Portuguese man-o'-war (Physalia physalis) envenomation". Ann Emerg Med 18 (3): 312–315. doi:10.1016/S0196-0644(89)80421-4. PMID 2564268. 
  14. ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0. 
  15. ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0. 
  16. ^ specialist from the University of Southampton appearing on BBC Breakfast program, date: 8am, Tue 19 August 2008.
  17. ^ a b Slaughter RJ, Beasley DM, Lambie BS, Schep LJ (2009). "New Zealand's venomous creatures". N. Z. Med. J. 122 (1290): 83–97. PMID 19319171. 
  18. ^ 3. Yoshimoto, C.M., and Yanagihara, A.A. Cnidarian (coelenterate) envenomations in Hawai’i improve following heat application. Transactions of the Royal Society for Tropical Medicine and Hygiene 96, 300–303, 2002.
  19. ^ Loten C, Stokes B, Worsley D, Seymour J, Jiang S, Isbistergk G (2006). "A randomised controlled trial of hot water (45 °C) immersion versus ice packs for pain relief in bluebottle stings". Med J Aust 184 (7): 329–333. PMID 16584366. 
  20. ^ Exton DR (1988). "Treatment of Physalia physalis envenomation". Med J Aust 149 (1): 54. PMID 2898725. 
  21. ^ Brodie: Venomous Animals, Western Publishing Company 1989
  22. ^ By Carla Scocchi and Dr. James B. Wood site. "Glaucus atlanticus, Blue Ocean Slug". Thecephalopodpage.org. Retrieved 2009-12-07. 
  23. ^ Morrison, Sue; Storrie, Ann (1999). Wonders of Western Waters: The Marine Life of South-Western Australia. CALM. p. 68. ISBN 0-7309-6894-4. 
  24. ^ "Tremoctopus". Tolweb.org. Retrieved 2009-12-07. 
  25. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.

External links[edit]