Sciency Words: Flora and Fauna

Hello, friends!  Welcome to another episode of Sciency Words, a special series here on Planet Pailly where we talk about the definitions and etymologies of science or science related terms.  In today’s post, we’re talking about two words:


So this weekend, I was thinking about alien life, as I often do, and it occurred to me that the words “plant” and “animal” are woefully inappropriate words to apply to extraterrestrial organisms.  That got me wondering if maybe the words “flora” and “fauna” would be better.

This is hardly a revolutionary insight.  Arik Kershenbaum talks about this in his book The Zoologist’s Guide to the Galaxy.  You see, in the cosmic sense, when we’re considering life across the entire universe, the words “plant” and “animal” are highly Earth-specific terms.  Strictly speaking, plants are organisms belonging to the kingdom Plantae, and animals are organisms belonging to the kingdom Animalia.  These kingdoms are two branches of the tree of life—Earth’s tree of life.  Not Mars’s tree of life.  Not Proxima b’s tree of life.  Earth’s.

Extraterrestrial life forms would belong to the kingdom… who the heck knows?  I guess astro-taxonomists will have to figure that out if/when extraterrestrial life is discovered.  In the meantime, would it make sense to use the words “flora” and “fauna” as generic terms for plant-like and animal-like aliens?  Initially I thought it would, but after doing some research, I’m not so sure.

Definitions of flora and fauna: In ecology, the words flora and fauna refer to all the plants and animals, respectively, found within a particular ecological region.

Etymologies of flora and fauna: The word “flora” traces back to the Latin word for flower.  Fauna comes from the name of an ancient Roman goddess of fertility.

So the words flora and fauna are not exactly synonyms for plants and animals; however, they do include the words “plants” and “animals” in their definitions.  And extraterrestrials, no matter how plant-like or animal-like they may be, would still have to be categorized as something else.

I still feel like referring to alien life forms as flora and fauna is better than calling them plants and animals.  Or at least it’s less wrong.  But it’s still not perfect.  In a distant, Sci-Fi future, new terminology may need to be invented.


I highly recommend reading The Zoologist’s Guide to the Galaxy by Arik Kershenbaum.  Obviously we do not know at this point what alien life might be like, but, as Kershenbaum argues, we can make some educated guesses based on the way life on Earth does (or does not) work.

11 thoughts on “Sciency Words: Flora and Fauna

  1. It seems like the words “animal” and “plant” long predate the current scientific definitions. The Latin etymology of “animal” seems to refer to breathing, and the etymology for “plant” to something stationary. I suspect scientists will have a hard time stopping people from just using those words for anything that resembles the traditional meaning.

    I do think if we discover extraterrestrial life, it will likely challenge many definitions (likely including “life”), and I agree new terminology will almost certainly be necessary.

    Liked by 1 person

  2. and is it yet clear to scientists whether they would have proteins, minerals, atoms and molecules, what would be their core reason d’etre for forming – could it be very different from the life on our planet?

    I suppose if all the stars (suns) are made of the same matter as our sun, then their planets would be made likewise…, but who knows ? With more concentration of one mineral than the other…?
    I love subjects like this, for they open windows into another way of looking…. and that is so precious to me in the same old, same old we all sometimes feel we live in.

    Liked by 1 person

    1. You raise some really good points. Aliens might be made of very different chemicals than we are, but they’d still be made of matter, and they’d still have to deal with the same laws of physics we do. As Kershenbaum argues in his book, those two facts mean we can put some constraints on what aliens would be like.

      Liked by 1 person

  3. It’s nice to think that we can, but could it not be possible that the laws of physics curve – bend, reshape when the universe cruves?

    They are made of matter and they have the laws of physics to shape, define them… Or is there a good reasoning for the laws of physics remaining as they are here?

    If the laws are the same, then their reason d’etre would be similar to ours… to arise and be shaped via their struggles and their joys… just like us…

    Liked by 1 person

    1. Modern telescopes have looked pretty far out into the universe. Obviously there’s still a lot we have to learn. The universe could surprise us at any time. But so far, the laws of physics as we currently know them seem to be consistent as far out into the universe as we are able to see.


  4. If we found aliens, we’d have another set of organisms to study. Maybe it’ll change how we define animals and plants in the first place!

    Liked by 1 person

    1. That’s probably the #1 best reason why we should keep looking. I don’t know what we’d learn if we were able to compare and contrast life on Earth with life from somewhere else, but we’d learn something pretty revolutionary. I am sure of that!

      Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.