Size relative to a 6-ft man
The IUCN Red List of Threatened Species is widely recognized as the most comprehensive, objective global approach for evaluating the conservation status of plant and animal species.
At relatively low risk of extinction
Likely to become vulnerable in the near future
At high risk of extinction in the wild
At very high risk of extinction in the wild
At extremely high risk of extinction in the wild
Extinct in the Wild
Survives only in captivity
No surviving individuals in the wild or in captivity
Not enough information available to make an assessment
No assessment has been made
Anyone unfamiliar with the biology of the venomous Portuguese man-of-war would likely mistake it for a jellyfish. Not only is it not a jellyfish, it's not even an "it," but a "they." The Portuguese man-of-war is a siphonophore, an animal made up of a colony of organisms working together.
Colony Structure, Tentacles, and Venom
The man-of-war comprises four separate polyps. It gets its name from the uppermost polyp, a gas-filled bladder, or pneumatophore, which sits above the water and somewhat resembles an old warship at full sail. Man-of-wars are also known as bluebottles for the purple-blue color of their pneumatophores.
The tentacles are the man-of-war's second organism. These long, thin tendrils can extend 165 feet in length below the surface, although 30 feet is more the average. They are covered in venom-filled nematocysts used to paralyze and kill fish and other small creatures. For humans, a man-of-war sting is excruciatingly painful, but rarely deadly. But beware—even dead man-of-wars washed up on shore can deliver a sting.
Muscles in the tentacles draw prey up to a polyp containing the gastrozooids or digestive organisms. A fourth polyp contains the reproductive organisms.
Man-of-wars are found, sometimes in groups of 1,000 or more, floating in warm waters throughout the world's oceans. They have no independent means of propulsion and either drift on the currents or catch the wind with their pneumatophores. To avoid threats on the surface, they can deflate their air bags and briefly submerge.