Manowar Jellyfish

The Manowar Jellyfish is a species of marine hydrozoan that is biologically not a true jellyfish, even though its features make it look like one. These creatures are extensively spread throughout their range and are known for their venomous and extremely painful stings.

Scientific Classification

P. physalis
Physalia physalis

Table Of Content

Scientific Classification

P. physalis
Physalia physalis

Physical Description

Size: The creature may be anything between 9 and 30 cm (3.5 to 11.8 in) in length, and may extend up to 15 cm (5.9 in) above the water surface. The weight typically differs with size.

Body: The main part of the body (above the tentacles) is soft and sluggish, and the entire creature is made up of four organisms, with each one being responsible for performing individual functions.

Pneumatophores: Also called ‘floats’, this organ is a long bladder, filled with gas, and is formed as an overgrown polyp resembling a closed bag. These are blue in color. The top part of the purple float has a hue of pink running through it.

Manowar Jellyfish

Sexual Dimorphism: Does not exist.

Is a Portuguese Man of War a Jellyfish

As mentioned, this creature does not fall under the group of true jellyfish, though its features make them look like one. They are basically siphonophores. Siphonophores are creatures that may look like one single organism but are basically colonial organisms made up of small individual creatures called ‘zooids’, each one of which has its own function for the survival of the entire cluster.

Similarly, the Manowar is also made of four different polyp types:

  • The pneumatophore or ‘float’, used to keep them floating on the water surface;
  • The dactylozooids, i.e., the tentacles, used to capture prey, as well as for defense;
  • The gastrozooids, used for feeding;
  • The gonozooids, used for reproduction.

Distribution & Habitat

They live in the warm, saline waters of the Atlantic, the Pacific, and the Indian Oceans.

Classification of Species

The man o war jellyfish has not yet been classified by the IUCN.

Manowar Jellyfish Sting

Manowar Jellyfish Pictures


Movement of the Manowar is not self-motivated, but generally passive, as they are driven by the ocean current and wind. These creatures cannot swim but float in colonies with the help of their pneumatophores.

Some Men-of-War are ‘left-sided’, while the others are ‘right-sided’. While the former drifts at an angle of 45° in the right direction from which the wind is blowing, the latter does the opposite. This difference in individual features is important on their part in order to spread more evenly throughout the warm oceans of the world.


Almost 70 to 90% of their prey are fish, both young (fry) and adults. They would also consume shrimp, other crustaceans, as also, other microscopic to tiny creatures like plankton.

Portuguese Man o’ war Jellyfish Sting & Venom’s Effects on Humans

The dactylozooids (tentacles) that are usually about 30 feet in length, use venom-spewing cells to deliver painful, neurotoxic stings. The venom is enough to kill most of their prey, and rarely humans.

Ways for medical sting treatment have been highly debated; however, in 2017, a study in the science journal ‘Toxins’ recommended vinegar to wash away the remaining nematocysts, if any, after the tentacles are removed. Finally, the affected area needs to be soaked in hot water with a temperature of 45° C (113° F) for approximately 45 minutes.

Manowar Jellyfish Images

Manowar Jellyfish Size

Mating and Reproduction

The time of reproduction is usually during the fall.  Among the four polyps, the one responsible for reproduction is called the ‘gonozooid’, which is made of gonophores, with the sacs containing ovaries in case of females, and testes in case of males.

The process of fertilization is external, with the creatures shedding their gametes into the water. The sperm from a colony fuses with the eggs of another colony.  Though, the reason for this process of this spawning cycle is still unknown.  However, this marine hydrozoan would also reproduce asexually by the process of mitotic division or budding.


  1. The top zooid, resembling a blob, is a bag that has the ability to capture and hold air, allowing the creature to float.
  2. The almost translucent appearance (with the blue hue) of the creature helps it camouflage very easily in the open waters of the ocean.


Manowar jellyfish are the natural diet of the loggerhead turtle and the ocean sunfish. They are also consumed by large octopuses like the blanket octopus.

Manowar Jellyfish Pics

Giant Manowar Jellyfish

Interesting Facts

  • The animal gets its name from its close resemblance to the 15th– and 16th-century Portuguese navy ships when they were at full sail. However, the name might have also originated from the helmets worn by the Portuguese soldiers during the same period.
  • Since these hydrozoans drift along on winds, tides, and ocean currents, it’s possible to predict where and when their groups will show up, e.g., the season of the Man O’ Wars in the Gulf Coast begins in the winter months.
  • The maximum recorded length of this invertebrate’s tentacle is about 165 feet.
  • The Indo-Pacific Portuguese man-of-war (P. utriculus), or ‘blue bottle’, found throughout the Indian and Pacific Oceans, is often confused for the Portuguese man-of-war (P. physalis) because of their very similar appearance; however, they are but related species.
  • The pain caused by a Manowar jellyfish sting usually faints within 30 minutes.
  • A ‘legion’ is an enormous group of these creatures consisting of over 1000 colonies, floating around together in the ocean.

Leave a comment

Your email address will not be published. Required fields are marked *

Subscribe our newsletter

Enter your email here to stay updated with the animal kingdom