World Building

How to Write Science Fiction and Fantasy


Creating New Alien Species
by Lee Masterson

Our human culture and physiology arose from our planet of origin's ecology. Our basic survival instincts were formed according to the surroundings into which we were raised. Our speech patterns also evolved according to the region into which we were born.

Why then, would a writer assume that an alien being, who looks different to the humans around him, would still walk and talk and think the same way, if he was raised in extremely different circumstances.

Creating New Life

Think about the climactic conditions you've decided to give your aliens to evolve. Let's guess what would happen to a humanoid creature who might have evolved on any given planet type.

Heavy-Gravity Planet
An alien who evolved on a planet with very heavy gravity is going to be short and stocky. The centre of gravity for a being here would need to be very low. Two legs would also not be very efficient for someone living there. Imagine the strain on the back and neck for this creature! Four, six or even eight legs would make travel easier on a planet like this. A centipede would have no problems. Housing probably wouldn't have a roof over four walls like we have. Gravity would bring it crashing down on their heads! Rain would be like getting hit with golf balls.

Cold/Dark Planet
A planet with almost no light would mean eyes become almost redundant. The other senses would be either finely honed, or the eyes would alter to suit the limited light available.

Of course, with very little light, this should also mean very little natural heat, so your alien race would need to evolve to protect against the cold as well.

A cold planet would see hairier humanoids trying to keep warm with body-fur. Fairer skin (fur) and eyes would also become more common.

Desert Planet
A planet with too much sunlight would result in human skin creating more and more melanin, giving much darker skin tones and hair/eye color.

Water Planet
A water planet should see humanoids evolving away from upright walking positions and into swimming or water-breathing type creatures over the centuries.

Low Gravity Planet
A very low gravity world would probably be a great place to evolve into something with very filmy, floaty tentacles or tendrils. Hair would be a great problem if it's constantly floating around your face all the time, so I'm guessing hair would be phased out over generations. Creatures here would be very tall and slender. Many creatures would be able to fly or glide comfortably in low gravity.
They'd really have a hard time invading Earth though.

Gaseous Planet
How about gaseous planets? How would a humanoid develop there? With not much to walk on and nothing really stable around them, would they become essence-of-human? Would they be largely gaseous beings, floating around in the ether? They sure wouldn't need legs.
Unfortunately, they probably wouldn't evolve with a solid bone casing for a skull. What would protect the exposed brain from predators? Would they have a brain in the sense that we know it?

Alien Beasts & Bugs

We've been focusing mainly on just humanoid creatures. What about considering what kind of native animals would have evolved to survive and hunt in those conditions? They wouldn't be anything like the creatures we know on good old Earth.

Heavy Gravity Planet
You wouldn't find too many flying predators or birds on a heavy gravity world Flying insects would also be rare, which means you'd be likely to find low-slung, many-legged crawlies getting around instead.

Water Planet
Birds probably wouldn't evolve well on a water world either, where land is scarce. The poor birds would be flying for days before finding somewhere to land. Of course, you could base your colonies of birds near to small islands, but what would you need to create to be the next predator up the food chain to keep populations down?

Low Gravity Planet
Low gravity worlds could have lots of flying or gliding insects, bugs, creatures etc. Imagine a centipede in really low gravity. It would almost be able to walk upright! Where's the need to keep evolving with hundreds of pairs of legs?

Desert Planet
Would heavily furred mammals like the ones we know survive in harsh desert conditions? Would their fur eventually phase out over generations, giving them more ample means of cooling off?
Reptiles would love to be able to bask in the sun most of the year

Gaseous Planet
As with the humanoids, would the insects also become essence-of-bug, cute little wisps floating around the ether?

Culture and History

What about the history of your alien race?

If they've been at war for two centuries without any peace-time, then they probably wouldn't have created a solid family unit in the sense that we perceive family. Nor would they have had time to create works of art or just pretty things. They'd get bombed!

If your alien society evolved on a desert planet, then much of the industry would occur at night and they'd sleep through the day. Water would become a precious item.

Communication is a factor too. On a water world, an alien won't be able to talk the way we do, by drawing in air then expelling it in a series of sounds via the vocal chords.

Governmental systems would be completely different, depending on whether your aliens lived in segmented clans or in larger city-societies.

As with any world creation, the only real limitations are your imagination. If you can imagine it, you can probably create a logical-sounding background for your alients too.

Let your imagination loose and see what new species you can create!

Copyright Lee Masterson. All Rights Reserved.

Lee Masterson is a freelance writer from South Australia. She is also the editor-in-chief and publisher of Fiction Factor ( - an online magazine for writers offering articles on improving your writing, honing your writing skills, writing your novel, free ebook downloads and much, much more. In what little spare time she has, Lee also writes horror, sci-fi and dark fantasy.


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