The Ecology of Worldbuilding

When constructing any world, understanding how an environment shapes the animals, plants, and people that live in it will help you provide a better and more enriching experience for your readers, allowing them to get lost in your world and not lost in trying to make sense of it.

Let’s start with some basic terms.

Worldbuilding is the process of constructing a fictional universe.

A biological community of interacting organisms and their physical environment.

The living organisms e.g. Plants and animals

The non-living components. e.g: Water, sunlight, soil type etc.

A large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra. Biomes are primarily categorized by the distinct plant and animal species in a certain climate and region.

Why These Terms and Concepts are Important

The abiotic components, particularly those which create the climate of an ecosystem, shape all of the life in it. For example, cold weather often means larger bodies for more mass to produce more heat and insulation (Consider: whales, polar bears, and large bird species such as snowy owls). There’s also a necessity for body covering like fur or feathers, unless a species has a significant amount of fat, like whales, and lives underwater or has evolved something like an anti-freeze.

Here’s a neat article on what marine life looks like in Antarctica : Marine Animals in Antarctica

Art by Jacob Atienza

Reptiles and amphibians, which are primarily ectothermic (meaning they rely on heat from the sun), are often rare or non-existent in extremely cold climates, unless you include birds—and yes, they are a form of reptile. Some exceptions exist, such as wood frogs and certain species of snakes that have evolved an anti-freeze, but because of the absence of heat in cold climates, reptiles and amphibians cannot thrive in these environments.

Large mammals and birds make up the majority of the fauna seen on land in cold and arctic climates and are often the apex predators (or top predator) in the water because of their adaptations, but that’s not to say that you can’t get big in the heat, organisms like alligators and anacondas are big and are often the apex predator where they live, but they are thriving in an environment they evolved specifically to fit in.

Art by Sung Choi

The above image shows a giant, rideable lizard in a snowy mountain scene. Even if this animal had evolved to thermoregulate (raise or lower its own body temperature), how does it insulate? It has no fur or feathers to protect it from the harsh, cold climate. Whales and other marine arctic animals have evolved to insulate with layers of fat, but they live underwater, out of the wind and snow. All of the mammals and birds on land in cold regions have feathers or fur to insulate and protect them.

Art by Yun Ling

Now we see a reptile mount in a desert-like environment to which it is much better suited. Other possible environments suitable for this species could include grasslands and jungle-type settings.

It’s not just climate that determines the evolution of a species, there are many components to consider when looking at the way an organism looks and behaves, for example, if an animal lives in an environment with a lot of water, they might be amphibious (spending part of their life cycle in water and part on land) or they might develop webbed feet for swimming, even when they can fly, like ducks and geese.


Bird of Paradise Male and Female

The previous components have all been abiotic, but when looking at the biotic components, things start to get more detailed or specialized. Reproduction has a huge role to play in this. For example, because of breeding competition, males of some species are larger than females. However, when looking at birds of prey, we see that the females are larger, because they are the ones who produce the eggs and primarily defend the nest. Breeding is also responsible for social behaviors such as mating dances and beautiful anomalies in nature like bioluminescence, which male fireflies use so that females can find them.

Other organisms such as glow worms and deep sea life also use bioluminescence to attract prey–which segways into my next topic.

Learn more about bioluminesence here.

One of the largest contributing factors to a species’s evolution is the food chain: is it predator, prey, or both? Whether that prey is a species of grass or the animal that eats the grass, an animal, plant, or fungus is shaped by what it eats and what eats it.

Many species of cats climb so they can drop out of trees or off a rock ledge and onto their prey. They are ambush predators. Rabbits have big eyes and ears so they can see or hear their predator coming. Snakes have venom to paralyze and subdue their prey, while horses literally have pogo sticks for legs to allow them to run away from predators.

Other great examples include giraffes who have super long necks to eat leaves from trees and whales who have specialized teeth to filter tiny sea creatures into their mouths when they open them.

Fire Diki by Anya Boz

Looking at this made-up species called Diki by the artist Anya Boz, we can ask ourselves all sorts of questions about its physical appearance to figure out its behavior and role in its environment.

When building your world and creating plants, fungi, and animals, here are some questions to consider and to help you get started:

  • Where does your animal, plant, or fungus live? Is it extremely cold, hot, or are there changing seasons?
  • Does it live in an environment with poor soil? Rich soil? Is it rich with life because of plentiful water and nutrients or is water rare and need to be conserved?
  • Does it live in extreme environments? e.g. Little to no light or extremely acidic water or soil? Does it live in vast, deep seas where it needs to cross long, empty distances?
  • What does it eat?
  • Does it have any predators?
  • Are there different genders? How does it reproduce? Does it need to attract a mate?
  • What special characteristics does it have and why? Apply what you’ve answered above. Does it have super long legs because it needs to run away or because its food is high up? Is it brightly colored to blend in or attract a mate?

Note: Males usually have brighter colors or are larger for breeding purposes, however exceptions do exist. Look up the angular fish or ball pythons for example.

A note on plants: Extreme climates usually aren’t too friendly to plants. They either survive by being small and well hidden or they defend themselves with things like spines and coatings of wax or toxins. Pine needles have a wax coating to protect them from the cold and cacti use needles to protect themselves from desert animals.

Lithops – Snagged from Amazon. No shame.

Lithops are a type of plant that disguise themselves as rocks. They live in cold and desert type climates where food and resources are few and far between. Because of this, they need to conserve water and energy by remaining small, but also disguise themselves as rocks and soil so they are hard to find.

Note: The designs at the top of some of the plants are actually windows for sunlight to get to the green chlorophyll, which they need for food production but hide so they are less visible to predators.

Do you have a plant species that needs to protect itself? Do they protect themselves with just spines or are those spines coated in a powerful hallucinogen to drive predators away? There are all sorts of neat ways that plants can defend themselves.

Example of Worldbuilding, the Good, the Bad, and the Unique

In Anne McCaffrey’s Dragonriders of Pern series, all the animals native to the planet had several things in common: they had a six-limb base anatomy and compound eyes (like flies). The native birds had front and back legs as well as wings—and so did the dragons, making their six-limb anatomy more believable. Whereas the species that came from earth all had a four-base limb anatomy. Examples included horses, humans, and dolphins (dolphins have evolved to lose their back legs, but they did originally have them).

Ok, so, I’ve thrown all this science mumbo-jumbo at you, and you might be wondering to yourself, is ecology applicable to other genres such fantasy? Absolutely.

Here’s an examples of when an author could have used research to be more accurate in their fantasy worldbuilding.

J.K. Rowling, Harry Potter and the Chamber of Secrets. The basilisk was a giant snake. Putting aside the fact that an animal that had just been seriously injured wouldn’t continue to chase someone–snakes don’t leave bones laying around because they swallow all their prey whole. Believe me, the bones don’t come out the same way they went in. In addition, snakes have an incredible sense of smell and most of them have relatively poor eyesight. The basilisk would have struck out at Harry when it cornered him because it would have been able to smell him.

Consider that many species of snake hunt in tunnels and in thick foliage or at night, having strong eyesight won’t help them. They need something else like a strong sense of smell. In addition, a lot of snake species have heat pits, which allow them to see body heat. There’s no way that basilisk would have missed Harry.

Shameless Snake Meme Grab

See the holes that dot the top lip of this ball python? They’re heat pits for seeing body heat. (Unicorn horn to help with the snake blow. I know people can be afraid of them. I hope this helped). 

Thor: The Dark World. The Dark elves evolved in a universe without light, so why did they have eyes? If there was no light (no sun, no stars, no heat, and literally nothing like the known universe and life as we know it), why would they have eyes? Eyes literally exist to take in light.

Another shameless Google grab.


In the movie Arrival, based on a short story by Ted Chiang, the alien species introduced is similar to a cephalopod. This makes quite a bit of sense considering cephalopods are extremely intelligent and because they are very different (physically and genetically) from other animals found on this planet (In fact, there’s a theory that our own cephalopods are aliens).

Arrival 2016

What was so unique about this film, was that the writer understood that a cephalopod creature would communicate differently than a human being, so a written language was used to communicate with the protagonist, because understanding body language or vocalization would have been much harder. The aliens wrote to the protagonist using ink, just as squids and octopi use for self-defense here on earth, so it’s not far fetched to believe that this alien species would develop a written language using the ink they might have evolved out of self-defense.

Worldbuilding doesn’t always have to be what eats what, it can also be about how a language is born from something like self-defense.

Closing Thoughts

Now, I’m not saying that you need to plot out whole ecosystems down to the niche mushroom that a black weasel feeds on that we’ll never see, but when constructing an alien planet or having a fantasy animal in your novel, the reader should be able to find an animal or fungus believable and have the sense that it belongs in the setting you’ve created.

Research is imperative for good worldbuilding, even in fantasy. Good research shows in writing and helps to create a rich world that people can get lost in. Take for example, the kelpie. At first, a fairy that eats people and shapeshifts into a horse may sound ridiculous, however, when you apply research and an ecological approach to it, it makes perfect sense.

What does the kelpie eat? Humans–and it attracts them by using a method known as mimicry.

Mimicry is a technique utilized by many predators. Think about predatory plants that disguise themselves as flowers, such as carnivorous pitcher plants. Insects are attracted to the flower thinking they’re going to get nectar, but instead get trapped by sliding into a water trap or by a sticky substance produced by the flower.

Kelpies disguise themselves as horses, so that humans will approach them. Once they touch or ride the kelpie, it takes them into the water where it devours them. Some sources even say that kelpies have sticky, adhesive skin to trap their prey—just like the flower.

When we approach the kelpie from an ecological point of view, we understand this fairy in a whole new way and it becomes more tangible to the reader.

In closing, I hope this crash course in ecology with a splash of worldbuilding has provided information and inspiration to assist you in your worldbuilding. All the best in constructing your world.


Cover Image by Michael Whelan

2 thoughts on “The Ecology of Worldbuilding

Add yours

  1. Awesome article, Sarah! Learned a lot of new terms today. BTW, if you and Josh haven’t found it already, there is a Butterfly Habitat in Cambridge. Be sure to check it out.


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