What’s a siphonophore?

In chapter 22 of Scribes’ Descent, Boxer says, “The glowy things’re in the shape of a box again. I wonder if they’re a colonial species, like siphonophores in the sky.”

The word siphonophores is so unusual that many readers may assume it to be a fictional term, but these exist on Earth. Here are some photos:

photo of a siphonophore. I believe this one is a Stephanomia amphytridis
Stephanomia amphytridis?
Photo of Marrus orthocanna
Marrus orthocanna
photo of Apolemia uvaria
Apolemia uvaria

These may resemble aliens from a video game, but they’re real creatures. Why do they look so different from each other? Siphonophore is not a single species, but a whole class of ocean-dwelling animals in the phylum Cnidaria. (Cnidarians have tentacles with stingers–like coral, jellyfish, and sea anemone.)

Here’s the full taxonomy of siphonophores, shown in Wikipedia:

While these share some features with jellyfish, siphonophores are quite different. The key lies in the term colonial.


Imagine giving birth to a clone of yourself that remains attached to you for life–the umbilical cord is never cut. Now imagine you have no legs, but this baby does, and so now you can move around for the first time. Then your baby has a baby of its own, which has tentacles with stingers that can form a net to catch prey and shoot paralyzing toxins at it. Now you can finally eat! And that umbilical cord connects all of you, acting like a shared circulatory system. This is a siphonophore: not a collection of organs to form a body, but a collection of bodies to form a colony.

Every new body attached to the colony adds a distinct ability that the other bodies lack. In siphonophores, each body is called a zooid. If you cut any zooid free of the others, it will die for lack of the abilities found in the rest of the colony. This isn’t true of other colonial animals like coral, which are made up of many tiny polyps, each of which can survive apart from the others. Because siphonophores can’t regenerate or live independently, it seems to exhibit traits of both colony and non-colony organisms. I’m having an existential crisis just thinking about this! Or, as Boxer would say, this boggles my boggler.

Different Bodies or Organs?

How do we know these special-function bodies are truly different bodies and not just attached organs to one big body? Zooids aren’t just organs because:

-they can move independently of each other (though within a limited range because of their connections)

-each zooid is similar to other solitary animals, such as jellyfish, having the same parts and structures.

Stranger Still

Some species can grow up to 154ft long, making them the longest animals on Earth–even longer than blue whales. The first siphonophore discovered was the Portuguese man o’ war, which lives at the surface of the ocean. It uses a float filled with nitrogen gas and carbon monoxide to sail by wind power across entire oceans.

photo of a Portuguese man-of-war
Portuguese Man O’ War

To learn more:


Have questions about siphonophores? Reply and let me know! In Scribes’ Descent, Boxer saw something that made him think of siphonophores floating in the air. Do you remember what he saw?

Writing update: So far, I’ve totally rewritten the first twelve chapters of Scribes Emerge (Scribes Series book 3). I’m shooting for 1,000 words a day, at least on days I’m not judging homeschool speech and debate tournaments.

See you next month,
Dylan West

Leave a comment