Portuguese man-of-war is a floating creature found in warm oceans throughout the world. Although it resembles a jellyfish, it actually consists of a colony of hundreds of members.
The colony begins with just one larval member. As it grows, this original member produces new members of several different types, by a process called budding (see Reproduction (Through asexual reproduction)). The original member develops into a blue, balloonlike float that is filled with gas. This structure keeps the colony afloat. It also acts as a sail, catching the wind and moving the colony about.
The other members of the colony hang from the float. Stringlike parts called tentacles catch food. When touched, the tentacles discharge poison that paralyzes and kills fish. The tentacles then haul the prey up to tube-shaped members that digest food for the entire colony. Other members produce the eggs and sperm necessary for reproducing new colonies.
A large Portuguese man-of-war may have a float 10 inches (25 centimeters) long and tentacles 30 feet (9 meters) long. The Portuguese man-of-war was probably named by sailors, who thought the animal’s float resembled a type of sailing ship that was called a man-of-war.
The Portuguese man-of-war often stings swimmers. Although it is rarely fatal, the sting causes a severe skin rash, extreme pain, nausea, and breathing difficulties. A Portuguese man-of-war washed up on the beach remains dangerous and should not be touched.
