Portuguese Man-of-war

• It is not one animal but a colony of specialised zooids working as a single organism.
• Its tentacles can trail as far as 50 metres.
• Although it looks like a jellyfish, it is in fact a siphonophore, a different group of cnidarians.
• biologíaIt is not one animal but a colony of specialised organisms (zooids) that work together as though they were one.
• It is not a jellyfish: it is a siphonophore, a colony of specialised individuals called zooids that cannot live apart. Some form the float, others catch prey, others digest and others reproduce.
• The gas-filled float acts as a sail. Because it leans to the left or the right depending on the individual, half the population sails downwind one way and half the other, which stops them all from stranding on the same shore.
• Its fishing tentacles can trail tens of metres below the surface.
• The sting is still painful long after the animal has died, even stranded on the sand.
• The first Nobel Prize connected with jellyfish went in 1913 to Charles Richet for the discovery of anaphylaxis, made with Paul Portier and arising from experiments with Portuguese man o' war venom.

Skeleton type

Invertebrate - no skeleton, a gelatinous colony of specialised organisms

Habitat and environment

Warm tropical and subtropical waters of every ocean, especially the Gulf Stream, the Gulf of Mexico, the Caribbean and the Sargasso Sea

Birth weight

A planula larva ~2 mm long

Size at birth

A planula larva ~2 mm long (the same figure as above)

Sexual maturity

Not applicable in the usual sense (a colonial organism that reproduces by asexual budding from the polyp stage)

Gestation / incubation

No gestation; it develops from a planula larva to an attached polyp and then, by budding, to a mature colony

Litter / clutch size

Not quantified precisely in the sources consulted

Sources consulted: University of West Indies (OGATT); National Geographic; Ocean Info; NOAA Ocean Service; Wikipedia (Physalia physalis); Nature Scientific Reports (morphology study)