World-building 105: Here Be Dragons

Posted on Tuesday, October 7th, 2014 at 16:59

This is the latest post in my series on world-building and I intend to talk about Ecology. Now you may be thinking, “I just have a fantasy world, of course there are dragons everywhere,” but as always the devil is in the details.

Darwin And The Dragon

Most people know what Evolution is (although they usually have no idea how it actually works), and for world-building it makes a lot more sense to think in terms of Evolution to build sensible rounded worlds (even if they are flat). Of course the gods may be responsible in the world, but for building Eco-systems evolutionary rules are a great way of keeping things straight, and making for believable worlds.

Evolution causes gradual changes in populations over generations, adaptations that serve the species are preserved from generation to generation and those adaptations that do not may cause a species to fail, but we don’t have time to do that, instead we need to think about the processes that take place. Let’s take a look at how dragon’s might have evolved for an example of how a fantastic evolution might work.

First we’ll identify what we actually mean by a dragon, there are several types that we can categorise and look at:

  • European fire breathing dragon: The classic dragon, it has scales, wings, a pointed tail and four legs. Oh yeah and it can breath fire.
  • Wyvern: has scales, its forelimbs are wings and a long tail that has a stinger.
  • Oriental dragon: has four legs, a long serpentine body and can fly without wings.
  • Lindorms and Wyrms: tend to be little more than giant snakes, they may have venomous breath or spit fire.

Lindorms and Wyrms seem to be the easiest to explain in terms of evolution. As we know snakes can get pretty big (and prehistoric snakes were enormous), Spitting Cobras seem to have venomous breath, but breathing fire is a tricky one to cover scientifically (not that people haven’t tried). We’ll look at a possible mechanism later.

Pterasaurs on the ground.

Seriously these guys were as big as Giraffes (or Camelopard if you prefer)!

The Wyvern is also easily explained in terms of evolution, essentially being nothing more than a reptilian bat, or Pterosaur. Some of which were probably venomous and certain species such as Dimorphodon had long tails that have an interesting tail shape, and the largest of the Pterosaurs were huge, imagine a flying giraffe, that’s pretty terrifying. The evolution of the Pterosaur is quite well documented, from gliding long-legged lizard to true Pterosaurs. Once the form had evolved in a small flying reptile it got bigger and stronger over time.

The Oriental Dragon is almost impossible to “evolve”, it flys without any obvious wings, is scaled and furred (which isn’t quite as impossible — Armadillos seem to manage something similar), and is depicted as intelligent and magic using. There are a few ways that these creatures could actually exist (especially if magic is part of the evolutionary process), with a large complex brain and some sort of buoyancy sack that allowed them to float.

Image from Flight of Dragons

The Flight of Dragons tries to explain how several tonne fire-breathing lizards might be.

The European Dragon seems to be similarly intelligent to the Oriental types (at least some of the time), and also flies, but it has wings (in addition to four legs — which is a hexapodal bone structure that has never evolved on Earth as far as we are aware, some evolutionary biologists may even claim that this structure is impossible in an endoskeleton) and it breathes fire (another impossibility some say). The hexapod body plan of the dragon is difficult to explain in terms of evolution, for our world as most vertebrates have a four-limbed structure, but there are occasions where conjoined twins have six limbs, it would conceivably be possible that such a conjoined twinning could become the norm for a species, allowing one ‘twin’ to evolve wings while the other kept legs, it is perhaps no coincidence that the European dragon includes multi-headed forms such as the Hydra. Although the regrowing of severed heads is difficult to explain in true biological terms.

The Novel (and later movie) ‘The Flight Of Dragonsgave very good explanations for how these flight and fire-breathing traits may be related, with the dragon producing vast amounts of hydrogen in its guts that provides additional lift and giving a suitable fuel to provide the flaming breath. Personally, I think that dragons would be more likely to use a chemical reaction similar to a bombardier beetle to create the flaming spittle. Essentially spraying bio-napalm, in which chemicals heat and spontaneously explode into flame. But the lighter than air flight of the dragons in the books would explain the flight of the Oriental Dragon. A combination of modified saliva glands, digestive gasses and hydrogen peroxide can easily be combined into a biological flame thrower.

While this can allow you to think about the evolution of the dragon, it tells us nothing about the world the dragon lives in. You can use the rules of natural selection to think about how any creature may evolve, but nothing evolves in a vacuum. It is the dragon’s prey, parasites and predators that govern the directions it’s evolution take, so we must consider the Eco-system that it evolved in.

Roles and Niches

Science likes to categorise things, even though nature usually presents us with a continuum. It is a model that we apply over and over again, in physics we use similar techniques to separate visible light from gamma rays and radio waves, even though they are all just differing frequencies of electromagnetic radiation, in ecology a similar trick is used to separate the various species of life into kingdoms, phylums and families, and to categorise the behaviours of the species to note similarities between them.

Fennec Fox

This is what happens if you take a grassland predator and adapt it to desert life and maximum cuteness.

This means that we can point at a fox and say it is a scavenger and carnivore that lives at the boundary of woods and meadows (and in the modern urban environment too), point at a rabbit and say it is a herbivore, that lives in a similar environment (although they have adapted less well into urban living), point at the grass and say it is a primary food-source that grows on certain soils, etc. When building an Eco-system you can use the same concepts to look at the world and identify niches that must be filled. Once you have defined an animal on one environment you can make suitable adjustments to it to have it spread to another environment.

So you can go ahead and draw in those grasslands and forests on the map, you can decide what fruit and nuts, and what berries or grains these plants might produce, leaves might be broad in dim, warm, wet lands, or needle thin in cold, dry climates, stalks may be edible or tough and woody.

These generate obvious environments that animals will live in, they also generate liminal spaces where one environment blends into another. Some environments (usually grasslands and occasionally forests) can support large herbivores, and large herbivore populations can support larger carnivores and large scavengers. When dinosaurs roamed the Earth the herbivores were huge sauropods, during the Pliocene they were mammoths, mastodon, wooly rhinos and giant elk, today they are elephants, cows and deer. The predators for each age were similar, large theropod carnivores hunted sauropods, sabre-tooth cats, dire-wolves and cave bears hunted the mammoth, and modern wolves, lions, tigers and bears hunt today.

Niche ecology is a complex study, worthy of years of research, but we can simplify the concepts to help us build a complex Eco-system of our own. Niches are a combination of role, environment (or biome) and size. In the last post we discussed the types of environments that you might be populating, but it wouldn’t hurt to include them here as a reminder:

  • Aquatic (sea/saltwater/ocean or freshwater, rivers, lakes, lochs, ponds, and meres)
  • Desert (Hot/cold/rocky and sandy types)
  • Grasslands (Steppes, meadows, prairies, moors, and savannah)
  • Forests (Jungles, Forests and woods)
  • Tundra (ice, snow, and permafrost)
  • Urban (mankind’s preferred habitat)
  • Farmland (usually cleared forests, kept for crops and grazing animals, as artificial as Urban)
  • The liminals or boundary areas: Between Aquatic and most others, we get Shore or Swamp, between Forest and Grassland we get glades, between Farmland and Grasslands we get hedgerows, etc…

Within each environment there will be the following roles:

  • Primary food producers (at least one organism that takes energy from the environment to grow) usually a plant, a lichen or similar.
  • Herbivores, an organism that eats the Primary food producers, usually an animal. Often specialised to a single food producer.
  • Carnivores, an organism that eats the Herbivores, often specialised to a single prey animal.
  • Scavengers, an organism that eats carcasses of both Herbivores and Carnivores, often a generalist, but specialised for a particular environment.
  • Opportunistic Omnivores that eat any of the above that they can tolerate, almost always generalists rather than specialists.
  • Parasites, each of the species above will provide possible niches for at least one parasite or disease. Parasites are often specialised to a specific species, but may have life cycles that cycle through the food web.
  • Detritivore, an organism that specialises in decomposing those parts of the food web that scavengers do not eat, including rotting plant and animal matter, often a role taken by bacteria and fungi.
Bear in a tree

Trees often support large Omnivores, sometimes literally, like this bear.

As you can see each plant ‘supports’ a herbivore (a specialised herbivore), a number of similar plants that share an environment may be eaten by a more generalised herbivore (perhaps even an omnivore or two), and so on. Even three or four plants can create a number of herbivores which will potentially have specialised carnivores as well as generalised ones. You can see how highly complex Eco-systems can be created from these simple roles.

To create our dragon we need simply consider it as a general predator, a scavenger or as a Detritivore (that eats ash – is that a Flaxivore?). To take the last interpretation (as it neatly explains the need to evolve a way of producing a flame, not that evolution really works this way, in fact) the small fire spitting lizard may originally have been a herbivore that evolved a way to cook a particular plant, its adaptation leading it to broaden its diet as it evolved hotter fire and greater ash production. Then again a chemical venom intended to paralyse a particular herbivore could have mutated and become flaming, increasing the success of the lizard allowing it to diversify its prey.

Over time species generalise when resources are tight, trying to exploit other food stuffs (fruits, nectar, eggs, fish, seeds, nuts, stalks, dung, ash — well, maybe not ash), leading carnivores to become omnivores and herbivores or vice versa, or they die out. During times of plenty species diversify, and specialise, as sub-species concentrate on a particular food stuff so adaptations that increase their specialisation seem to occur, often re-exploiting a niche that the last set of extinctions had killed off. In fact both processes are ongoing with some mutations generalising and some specialising, but only the external pressures of the environment force those changes for survival.

We see the largest and most prominent examples of these when major environmental impacts occur. Ice-ages, asteroid impacts and volcanoes change Earth’s environment and cause bottle-necks that kill off specialists, afterward a recovery occurs where the generalists begin to specialise once again.

Microfauna, Fauna and Megafauna (Oh my!)

Worm and Egg

These guys live in cysts on soybeans. They have their own predators and parasites too.

On Earth the sizes of creatures (and plants) are broken up into size categories. Biologists decided that there were only really three size categories, but a simple look around proves that there are probably more.

For each of these categories you can build animals and plants that fill that size category. They will often inhabit the same niches at different scales.

This is a scale list for fauna, Flora generally don’t get quite as small, but can be equally as massive, with the largest plants covering hundreds of square miles, or reaching hundreds of metres tall.

  • Nanofauna: The smallest life, tiny bacteria and viruses live at this scale.
  • Microfauna: The realm of the most common life, bacteria, zooplankton and moulds.
  • Macrofauna: The next most common life, the realm of arthropods (insects, shrimp and so on), but you’ll also find the smallest of the vertebrates at this scale.
  • Fauna: Most vertebrates live at this scale, as well as the largest insects and crustaceans. Fauna generally have a mass of up to 45 kilos.
  • Kilofauna*: The larger vertebrates begin around here, humans fit into this range, as do kangaroos and deer. Kilofauna have a mass of more than 45 kilos but less than a metric tonne (1,000 kilos).
  • Megafauna*: The larger vertebrates live at this scale, they have a mass of more than one tonne and are generally pretty big, most dinosaurs seem to live in this scale, as well as Rhinos, Elephants and the medium-sized whales.
  • Gigafauna*: The very rarest and largest creatures. Their mass can only be measured in tens of tonnes and has no real upper limit, the largest of the Sauropods were Gigafauna, as are most of the whales. The very oldest Dragons and Island turtles would also live in this scale.

*Biologists tend to combine these scales together as Megafauna, probably because there were no sauropods walking around on land when they started the categorising.

Grasses, Rabbits and Foxes

Rabbit and Fox populations graphs

You can see that rabbit populations fall fastest when fox populations are highest, for some reason.

Science likes simple models, and one of the simplest in biology is the Grass, Rabbit, Fox food chain. It teaches us how the producer (grass) is consumed by the rabbits, who are in turn consumed by the foxes. A meadow of grass provides plenty of food for a group of rabbits (and the mice, and voles, caterpillars, ants and so on), the population of rabbits can support a much smaller population of foxes (in fact in nature about 9 rabbits are needed for every two foxes, but rabbits breed quickly and foxes quite slowly).

Theres a lot of work that has been done on predator-prey ratios and all they have really proved is that it there is no stable ratio, but rather that the numbers drift along with each species a little out of phase to the previous one, if the grass dies back because of a drought, the rabbits numbers fall a little later, the foxes don’t start to starve until a little later still, by which time the dearth of rabbits (and the late rains) may be encouraging the grass to grow once again. Over time you can look at the average of such populations and see an average ratio, the ratio depends on factors such as the age and size of the creatures. Larger creatures eat more than smaller ones, but take longer to reach maturity.

In terms of biomass it is not uncommon to see numbers in the orders of 1,000-1,000,000 kilos of grass provides food for 100 kilos of herbivore, which in turn support 1-20 kilos of predator, although these numbers can vary massively with rich, energy dense foodstuffs and generally meat is more energy dense than plants (herbivores graze constantly carnivores eat once a day generally at most — although anteaters and whales do skew these figures).

In short there should be a lot more herbivores than carnivores, and herbivores tend to get larger.

Herbivores, Huge, Hooves, Horns and Hiding

If you consider ecology as an arms race then Herbivores (well prey animals, smaller carnivores and omnivores may also use these tricks) are all about the defences. Evolution has time and again shown that some defences are universal, here’s a list of the most common.


Huge, armoured and pointy, Triceratops pretty much have it all, if only they had hooves and camouflage skin they would be perfect herbivores.

  • Size: being big works, it helps you be strong, you lose less energy through heat and you can eat more.
  • Speed: running away is usually the best defence that an animal has.
  • Senses: a good warning system lets you start running away sooner.
  • Armour: having armour of any sort makes you less of a victim to weaker predators, but bony plates and thicker skins are heavy and so turn up on larger creatures.
  • Horns: useful for mating competitions and for fighting off carnivores. Horns tend to be the main weapon of herbivores (although a good kick is always on the cards), stegosaurs wore theirs on their tail, as did ankylosaurs (although they were more club like).
  • Poisonous: insects and some fish use toxins to make a predator think twice about eating a second one of their species.
  • Camouflage: for many prey species the ability to hide usually in a specific environment (including a herd of their own species) or with adaptive camouflage (like Cephalopods).

Carnivores, Canines and Claws

Predatory animals (the carnivores and omnivores) are also fighting in the same arms race. Evolution has generally equipped them with the tools they need to catch and eat their prey.

jumping spider

Snares, speed, deadly pounce, intelligence and venom, we’re lucky spiders are tiny.

  • Size: big prey? Be big, you will usually be smaller than your largest prey, but you may want to be big enough to eat some of your prey in one bite.
  • Speed: fast prey? Run faster and catch them. Successful predators are usually faster than their prey, but not by much.
  • Senses: if your prey is a hider you need to be able to find them. Predators usually have stereoscopic range finding vision, and a good sense of smell.
  • Armour penetration: big teeth and sharp claws can cut through armour.
  • Venom: whether a scorpion’s tail, a snake’s bite or the sting of a wasp, many predators have toxins they can attack with, often specifically evolved to poison a specific prey. Often, but not always, the predator will be somewhat immune to its own venom.
  • Stealth: somewhat similar to hiding the predator sneaks close to the prey until they can attack. This leads to predators having slinking, crawling, climbing and pouncing behaviours, as well as camouflage patterns and in extremely well adapted predators holographic image disruptors, well maybe not that last one.
  • Snares: whether a net, a web, or simply a sticky tongue many predators have developed snares of one sort of another. Spiders are nature’s best Snare hunters, and may have taught humans how to weave and catch fish, if myths can be believed.
  • Intelligence: predators are generally smarter than prey. Coordinated tactics, risk assessment and so on require a smart mind. Omnivorous predators generally seem to be smarter than pure predators as their intelligence is part of their overall adaptability, but that might be an anthropomorphic argument rearing it’s head. True intelligence is one of the greatest weapons of all, it can allow a much physically weaker force to multiply their strength through the use of tactics and weapons.

Building a world

Okay so we have looked at the systems and types of animals, although we have only Earth’s ecology to compare to, that’s okay for most fantasy worlds as they are very Earth-like. Most fantasy worlds just add a few Unicorns, a couple of Griffins, and a Dragon and they are done.
Science-fiction worlds can be much more complicated to build, because there is no standard we can compare against. We have no way of knowing how a being of pure energy might evolve, but we can probably be sure that if they did, something would evolve that could capture and consume that energy, and something else would learn to survive on their excretions.

Sandworm from Dune

Mmmh Shai-Hulud!

This may be part of the reason for those single environment worlds, as having a global desert or ocean neatly cuts down the work the author has to do in world-building.

In the case of Frank Herbert’s Dune series, for example, the majority of the life on Arrakis is part of the life-cycle of the Sandworms (less a few hopping mice and bugs which may have hitched a ride with humans anyway), but it works (in Dune’s case) because of the complex life-cycle the worms have.

They exist as microfauna in the sand, behaving more like a plant than an animal, they grow and multiply as sand-plankton,  in time they grow into the water-trapping sandtrout (which is about the size of your hand), that dried out Arrakis eons ago. Finally, when the sands are dry enough, they grow into the Great Makers, who feed upon the sand plankton they spawned from (and anything else that makes a rhythmical noise upon the surface).

This ecosystem worked in the books partly because of the complexity of the (essentially) closed life-cycle of the sandworms, but also because the political and social systems in the universe that make the Freman less than forthcoming about the details of their homeworld, and for good reason.

Food webs and cycles

A food web

Food webs can help you plan and arrange a whole eco-system.

When we are building worlds and examining ecosystems it can often be very handy to draw up a food-Web. Specialised creatures are easy to see on the web, each lifeform has its own predator and a parasite (or two) as well as a detritivore or scavenger that follows it around.
Generalists are harder to place on the web-of-life as they often connect many species together (just think about all the food types that humans eat and imagine trying to draw a food-web that included everything from wheat and seaweed to shark and pig, and we support many parasites from arachnids and worms to fungi and plants).

It is worth doing though, and don’t be afraid if you have large populations, to double up on parasites and predators (which may be Generalists rather than specialists and eat a variety of prey animals).

Be sure to check your food-web, if all the energy flows from plants into animals, and then eventually down to some worms, those worms will become the dominant species, and eventually your plants will die off from lack of nutrients as the energy and nutrients pool within the worm population, if this was happening on Earth one of the Omnivores (or General Carnivores) would immediately add some worm to their diet, so that the energy flowed back up into the system creating a cycle (at the very least the worms might be fertilising the plants that start the system off).

It all makes your world a more interesting, complex and believable place.

That’s about it for Ecology, have fun populating your worlds. The next post is on those most tricky of creatures, the sentient beings of your world. The people, their culture and history. I might even have a few things to say about created languages and the like.

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