Portuguese Man o' War



The Man o' War floats on the surface of tropical waters throughout the world. They can also drift into colder waters, and survive well in many areas. They are very common in Australia, The Caribbean Sea, the Indian Ocean, and off the cost of California. In addition, last summer there were swarms of Man o' Wars spotted in the waters off of Great Britain.


Though the Man o' War looks like a jellyfish, it is actually a Siphonophorae, which is an order of colonial organisms. It is made of of four types of polyps, called the pneumatophore, dactylozooid, gonozooid, and gastrozooid.


The pneumatophore is the part that is above the water. It is translucent with a blueish tint. It is a gas filled bladder which acts as a sail, since the Man o' War cannot move itself. Thus, where it goes is controlled by the winds and tides. Because of this, the pneumatophore is tilted 45 degrees either left or right, so if winds would bring a population to predators, only one half would be in danger, and the other half would be fine.


The dactlyzooids are the Man o' War's tentacles, and contain the nematocysts. They can reach up to 165 feet in length, but on average are about 30 feet long. In addition, they contain contractile cells which pull the food up towards the body for digestion. The poison contained in them can either stun or kill prey, depending on the size of the nematocyst which it is released from. The poison is almost never lethal to humans, though it is extremely painful, and can leave whip like marks on the victim.


The gastrozooid is the polyp responsible for digestion. Once prey has been dragged near it, the gastrozooid releases various enzymes into the water which can digest proteins, carbohydrates, and fats.


This is the polyp responsible for reproduction. Every gonozooid is either male or female. Around the fall, it will release many gametes into the water, where they meet with the gametes of another Man o' War.


Kingdom: Anamalia
Phylum: Cnidaria
Class: Hydrozoa
Order: Siphonophora
Family: Physaliidae
Genus: Physalia
Species: P. physalis