It Turns Out The Portuguese Man-Of-War Isn’t A Jellyfish

A day at the beach is a great way to pass the time, especially in the summer. However, you have to be careful at the coast, especially if you go in the water. Depending on where you are, dangerous animals could appear and put your life in danger. That includes the Portuguese man-of-war, an animal that many people assume is a jellyfish but actually isn’t.

The Portuguese man-of-war isn’t a jellyfish because it’s formed of multiple entities
Source: Getty Images

The Portuguese man-of-war isn’t a jellyfish because it’s formed of multiple entities

When looking at a Portuguese man-of-war, it’s probably not hard to see why people assume it’s a jellyfish. The creature is transparent, has no spine, and has tentacles that can sting. These are all features that the average person associates with such creatures. However, there’s apparently a fundamental difference between the two – the Portuguese man-of-war isn’t a single entity. That might be hard to believe looking at it, but this creature is actually a floating colony formed of small, genetically identical entities.

The Portuguese man-of-war isn’t the only creature that functions like this

While this might sound unique, that’s not actually the case. That’s because a Portuguese man-of-war is a siphonophore, a class of marine organisms where the species all have a similar structure. According to biologist Catriona Munro, his jellyfish-like creature consists of bodies known as zooids that are basically akin to free-living individuals. That’s the same for other siphonophores. While the colony functions as an individual, the zooids within the colony don’t.

The zooids in a Portuguese man-of-war serve different purposes
Source: Getty Images

The zooids in a Portuguese man-of-war serve different purposes

The amount of zooids that make up a Portuguese man-of-war varies quite significantly, depending on the size of the creature. Some may have hundreds, while others might have thousands. What’s more, these zooids don’t all serve the same purpose within the colony. For instance, gastrozooids deal with the breaking down of food that is captured by the dactylozooids.

The Portuguese man-of-war relies on the wind to swim

Another of the zooids worth mentioning is the pneumatophore. In each Portuguese man-of-war, there’s a gas-filled sac that supports the other zooids and makes the colony float. Unlike jellyfish, this creature cannot actively swim and instead relies on the pneumatophore to catch the wind to move. As it does so, its tentacles hang in the water and sting whatever it comes into contact with, which can then be dragged up to the gastrozooids.

The Portuguese man-of-war can do a lot of damage with its stinging tentacles
Source: Flickr/Sean Nash

The Portuguese man-of-war can do a lot of damage with its stinging tentacles

While the Portuguese man-of-war might not be a jellyfish, it can still sting like one and cause harm to many animals, including humans. These tentacles can allegedly stretch as much as 100 feet and are capable of causing pain, vomiting, headaches, and digestive issues. There’s also a risk to life in humans, although this isn’t that common. It only really happens if the tentacles wrap around the body and discharge a large number of stinging cells.

So, you now know the difference between jellyfish and the Portuguese man-of-war. Somehow, though, we doubt you suddenly feel any safer coming into contact with the latter at the beach.