Last time I talked about coming up with fantasy creatures. I neglected to mention that there are some very weird and wonderful creatures right here on our own planet that can give you inspiration. Look at the insect world or the (very) deep sea, particularly around volcanic fissures on the sea floor. Trust me, if you’re stuck for ideas you won’t be for long.
But this leads me onto something very important when considering your fantasy creatures, namely that their environment will have dictated their evolution. A creature is not just a collection of limbs, skin and internal organs. It doesn’t spring to life, fully-formed, anywhere except in your imagination. If you want it to be more than words on a page, you must make sure that it fits with its environment.
For instance, how many wild horses have you heard of that exist in the jungle? There are two very good reasons for that. Horses’ legs are their weak point. If they trip over an exposed root and damage a hoof or a leg, that’s it for them. They’ll either starve to death or get eaten, in very short order. Wild horses are usually found on open grassland where they can see predators coming and get up a good level of speed in order to escape. The second reason is that they eat grass. In a jungle where the canopy blocks light from large amounts of the forest floor, there is not an overabundance of grass. Score two for the open grassland.
On the flipside, can you imagine a giant panda living on open grassland? Even if it had evolved a slightly less dramatic colour scheme, it could never wander more than twenty feet from a tree without running a truly dire risk of being killed by a quick-thinking predator.
When you think up a fantasy creature, think about the type of habitat you are going to put it in. This will, to a large degree, dictate a number of factors, its size, its diet and how it gets around being the most important ones. If it lives in high mountains and doesn’t fly, it will neeed to be quite small and nimble (think mountain goat). If it flies it can be large or small. If you want it big, it’s going to need wings, otherwise it simply won’t be able to find food. Let’s face it, the only really large animals in mountainous areas (not counting great big dragons, if you like that sort of thing) are the birds. The South American Condor is one of the largest birds in the world and is found in the Andes mountains of South America. These rise to an average of 13000ft above sea level. So the birds obviously have some scheme for living with low oxygen levels, too.
Whether you situate your fantasy creatures in mountains, plains, at sea level or underwater is entirely up to you. As I have already pointed out, it is your world and you can do what you like. Unfortunately, if you want your readers to be right there with you, it is going to have to make sense. Not necessarily in terms of Planet Earth, but you will need to set up some kind of world system wherein what you want to do does make sense. Suspension of disbelief will take you a long way, but even the most cooperative imagination has a cut-off point. Get it right and you will make fans of your readers. Which is well worth worth doing.