Anyone unfamiliar with the deadly Portuguese man-of-war would perhaps mistake it for a jellyfish. Not only is it not our conventional jellyfish, it’s not even an “it,” but as per the latest research, a “they.” The Portuguese man-of-war is considered a siphonophore; an animal made up of a colony of tiny organisms working together.
The Portuguese man o’ war, also known as a bluebottle, the man-of-war, or floating terror, is a group of marine animals located in the Indian Ocean and Atlantic Oceans.
Let’s look at six fun facts about this unusual marine creature.
- Discovered primarily in subtropical and tropical waters, the Portuguese man o’ war lives at the ocean surface. The pneumatophore, or the gas-filled bladder, remains at the surface while the rest is submerged. Portuguese men o’ war sadly have no physical means of propulsion and move passively, driven by the currents, winds, and heavy tides. Powerful winds may drive them into beaches or onto bays. Often, discovering a single Portuguese man o’ war is followed by finding several others in the vicinity. Because they can sting (poisonous) while beached, the arrival of a man o’ war washed up on a beach always lead to the beach closure.
- Like all known siphonophores, the Portuguese man o’ war is extremely colonial: each man o’ war comprises several smaller units called zooids that hang in clumps from under a gas-filled, large structure called the pneumatophore. New zooids are often added by budding as the strong colony grows. The bladder, or pneumatophore, is the most prominent part of the man o’ war. It is tinged blue, translucent, pink, purple, or mauve, and maybe 3.5 to 11.8 inches (9 to 30 centimeters) long, and rises as high as 6 inches (15 cm) above the water.
- The pneumatophore works as both a flotation device and a sail for the entire colony, allowing the settlement to move with the steady wind. The gas in the pneumatophore is part CO (carbon monoxide) around 0.5-13%, which the animal actively composes, and part atmospheric gases (oxygen, nitrogen, and some noble gases) that diffuse in from the neighboring air. In the event of an outside attack, the pneumatophore can be deflated, allowing the colony to submerge temporarily.
- The colony feeds and hunts through the cooperation of two kinds of zooid: tentacle-bearing zooids and gastrozooids. The tentacle-bearing zooids (also called dactylozooids and tentacular palpons) are primarily equipped with tentacles, which are normally about 30 ft (10 m) in length but can reach over 100 ft (30m). Each tentacle bears coiled, tiny, thread-like structures called nematocysts. Nematocysts inject and trigger venom on contact, paralyzing, stinging, and killing larval or adult fishes and squids.
- Man o’ war is dioecious, meaning each colony is either female or male. Gonophores producing either eggs or sperm (depending on the gender of the territory) sit on a mysterious yet scary tree-like structure called a gonodendron, which is assumed to drop off from the colony during the process of reproduction. Mating occurs in the autumn when sperms and eggs are shed from gonophores into the sea. As neither fertilization nor early development has been directly discerned in the wild, it is unknown at what depth they usually occur.
- This dangerous species is responsible for up to 5,000 human stings in Australia each summer, especially on the east coast, with some others occurring off the coast of Western Australia and South Australia. Stings sadly cause a sharp pain to humans, leaving red, whip-like welts on the skin that generally last two or three days after the first sting, though the discomfort should subside after about a couple of hours.