How To Create An Alien Species In 3 Stages

Alien World

It’s Alien August over at — which means a whole month of extraterrestrial goodness invading their website, and dozens of science-fiction writers filing in their creature profiles to win the grand Alien August Competition. And — squee! — an autographed copy of my novel The Deep Link is part of their Prize Package! Isn’t that awesome?

Of course now is the perfect time to write a post about creating alien species.

I love all aliens—from little green men, to large bionic killers (like the drool-worthy Emranti in my novel)—so I’ve put together a guide to creating an alien species from scratch. I tried to stay brief (really, I did) while still being comprehensive, but there’s just so much to say on this delicious geekery that is creature creation, so bear with me.

*cracks her knuckles*

Off to the lab!

There are at least as many ways to create aliens (or magical creatures) as there are writers. No two creative minds truly think alike. We take very different approaches to creating characters for our stories, to developing plots, or to picking settings. And when it comes to creating new species (or putting our own spin on already existing ones), our approaches vary even more.

Some come up with a specific alien character, and work their way back to how his species must function and what its history (and world of origin) is. Some take a particular interest in an existing species of our world or a known fictional world, and make a significat alteration to it, then work their way out from that into all directions. Others fall in love with a celestial body, and envision what type of creatures might evolve in that environment.

Which ever approach you take, whether it’s top down, large scale to small, or the other way around, there are some big, important aspects you need to consider in order to achieve one of the most important criterias of good speculative fiction: internal consistency.

Suspension of disbelief is the blood in our story’s veins, and to keep it flowing unobstructed as we introduce foreign bodies (*cough* aliens *cough*) (ouch, sorry, that’s gotta be the worst pun in the history of all puns, I’ll go sit in the corner for a minute), we should pay attention to following things.

1. The aliens’ role in your story

Writers argue about many things, most of the times, but on one thing we all agree: Story comes first. So before you set out to create your aliens, you must first understand what kind of aliens your story needs. What kind of aliens would push the plot forward, and have the biggest impact on readers?

Answer the following questions:

  • Are the aliens good or evil? Neither? Somewhere in between?
  • Do your aliens have to be intelligent, socially evolved, maybe even technological? Or are monstrous beasts enough to satisfy the story’s needs?
  • Do you need your characters to communicate with the aliens? How can you make communication difficult? (Consider these Interspecies Information Exchange problems)
  • What do the aliens in your story want? What are they after? What is your characters’ position in relation to that?

The answers to these questions will largely determine the direction in which your species development will go, and how much you have to focus on specific things.

2. Big-picture species  and world design

Worldbuilding is great fun. You can go all the way from writing sketches, to generating huge amounts of material for your aliens, but if only a fraction of that material is really necessary to tell a riveting story, then all that wonderful worldbuilding work isn’t really writing, is it? *narrows her eyes* It’s procrastination. Admit it. Delicious procrastination, but procrastination nonetheless. Trust me, I’m guilty of that as much as everyone, so I know. I know. Let’s keep to the essentials here.

To design your alien species and stick to the basics, develop a brief, grand scale information about The Origin Of Your Alien Species and investigate following things:

  • Biological peculiarities
    – do they have tentacles, 10 limbs, are they humanoid, and if so just How Much Likeness to Humans is Plausible?
  • Social life, and by extension Sexual life because no species is entirely created in a vat
    – in fact, procreation and social structure are tightly related, and you can’t develop either properly without at least considering the other and its impact. Besides, it’s fun imagining how your aliens might do the rumpy-pumpy. You don’t even have to go very far to get inspired, as our very own earthly fauna has some rather ‘outlandish’ things to offer, as I’ve noted in Alien Sex – The Stranger, The Better.
  • Cultural diversity and values
    – political structures, religions, sub-races, economy, all of these need at least a cursory glance (and a few sentences in your notes) just so nothing glaring slips you by to be pointed at in a reader review later.
  • Psychology
    – perhaps the most important aspect of your species—at least pertaining to your story—is the psychological aspect of the individuals in your species: their instincts and how they affect their thinking, their emotions and how they influence their decision, their propensity toward something or their aversion to another. All of this matters if it’s big scale, such as the human propensity toward comfort and satisfying immediate needs, even at the cost of the future of our entire species.

If your story ventures into the actual world of these aliens, instead of having them drop in on our world(s), you must also do some worldbuilding. How much will depend on how much of a role the setting plays in your story. I’d advise you to at least conside the following Top 5 Worldbuilding Must-Haves:

  • Basic infrastructure
    – housing, transporation, industry, energy storage and distrubution, food production and delivery, waste disposal, etc.
  • Diversity
    – different countries/states/regions, ethnic variants, social roles, jobs, hierarchies, etc.
  • Completeness
    – some things habitually get lost in worldbuilding, unless they’re specifically needed, and we ought to remember to at least give them a cursory glance, such as: the legal systems, burrial rituals, infant care systems, medical systems, recreational facilities, etc.
  • Consequence
    – nothing in a civilization is isolated, and every choice we make when we develop our alien world will have consequences on all other aspects of it. You don’t have to investigate all dependencies (that’s not even possible for our world, and we have tons of knowledge about it at our disposal), but at least think about the things which you’ll actually use in your story.
  • Immediacy
    – every world has a history, and every history is propped up by a handful of major events which have influenced the evolution of the species. Which are they, for your alien world?

Go as deep as you need for your species and world to feel natural, logical, and real.

If you’re really pressed for time, or aren’t such a big fan of extensive, exhaustive (and exhausting) worldbuilding (in which case #highfive because neither am I, but don’t tell anyone or I’ll have a lynchmob of sci-fi nerds hunting me down) you can just run through these 13 Worldbuilding Questions and you’ll be just fine.

3. Pick your alien character(s) wisely

While it may be incredibly tempting to pick the top of the crop and make your specific alien characters have all (or the very best) characteristics of your species, remember: story comes first. And no one likes a predictable story, so choose wisely.

Your alien characters must fulfill the same criteria as your human characters, if not more (probably more). Hence, they must:

  • be interesting and unique, not stereotypical and two-dimmensional;
  • have problems of their own, personal, specific problems that only pertain to them as a person, not their species as a whole (too generic);
  • have goals and interests of their own, which should ideally clash with everyone else’s, even their own fellow aliens;
  • have a character arc of their own, the size of which should be determined by their importance to the story. The more important the alien character, and the more screen time they get, the bigger their character arc.[Read more about The 3 Types of Character Arcs and what they must cover to work.]


That’s basically it.

You’ve figured out what your story needs, developed your species logically, and picked memorable individuals that can push your story forward and complement your human characters. There are no limits to what you can come up with, really, as long as you stay consistent and you know, sane.

My head is full of ancient aliens


For some additional giggles, and maybe to check if a cliche may have slipped into your worldbuilding unnoticed (we’re all prone to this, it’s the media’s fault, it’s brainwashing us, I tell you!) take a peek at following lists:

13 Aspects About Aliens You Shouldn’t Ignore

13 More Aspects About Aliens You Should Consider

Damn I love those lists. Gotta write another one soon.

But in the mean time I’ll go check out the crazy alien profiles on and see if I can spot the winner beforehand!

Published by Veronica Sicoe

Science Fiction Author — I deliver the aliens.

12 thoughts on “How To Create An Alien Species In 3 Stages

  1. Thanks for letting me know about the contest. I’m going to be finishing a first draft in the next couple days.

    It’s something to do as I prep for my next project. Plus, you know, aliens.


  2. Pingback: Brown Blog
  3. Any advice on making alien plants and animals? My story has humans colonizing a planet full of non-sentient life. I need to figure out a ton of plants and animals before they get there.


    1. Think about the climate and conditions of the planet, this will play a huge part in how plants and animals have evolved on that planet. Once you have some general ideas you can either start with a plant, figure out what type of animal would eat that plant and what animal would eat that animal and so forth, or do the reverse. Just remember that all these things, planets, plants and animals, influence each other in how they evolve and grow. Think of how the plants adapt to protect themselves from their predators, and how the animals adapt to survive the various climates of the planet.


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