What Makes the Portuguese Man-of-War Unique?

portuguese-man-war-unique Credit: Wild Horizon/Universal Images Group/Getty Images

While the Portuguese man-of-war may look like a jellyfish, it's actually a siphonophore. Also known as simply "man-of-war" or "bluebottle," this complex creature is a colony of smaller individual organisms known as zooids. Though separate, the organisms that make up the Portuguese man-of-war work together and rely on each other for survival.

As a collection of individual beings, each of the man-of-war's parts, such as the tentacles and the uppermost part known as the pneumatophore, function as separate entities known as polyps. Each polyp contains a different kind of zooid that serves a specific function, which is why every part of the Portuguese man-of-war is essential for survival.

The man-of-war's unique physical makeup isn't the only thing that sets it apart from other living things that are found in the ocean. Unlike jellyfish, the man-of-war floats and is moved by ocean currents rather than using its tentacles or pneumatophore to move around. They can submerge themselves temporarily, but this is their only means of independent movement. These siphonophores typically group together in large clusters and float near the surface of the ocean in warm climates. Though they technically aren't jellyfish, man-of-war tentacles create painful stings when they make contact with human flesh; the stings aren't fatal except in the case of allergic reaction.