The Portuguese man o’ war, (Physalia physalis) is often called a jellyfish, but is actually a species of siphonophore, a group of animals that are closely related to jellyfish. A siphonophore is unusual in that it is a comprised of a colony of specialized, genetically identical individuals called zooids — clones — with various forms and functions, all working together as one. Each of the four specialized parts of a man ‘o war is responsible for a specific task, such as floating, capturing prey, feeding, and reproduction. Found mostly in tropical and subtropical seas, men of war are propelled by winds and ocean currents alone, and sometimes float in legions of 1,000 or more!
Original article: What is a Portuguese Man o’ War?