I’m not through with those dragons. Not by a long shot. The last article on them was fairly general in scope, and you can read it here to catch up if you want but the long and the short of it, is they’re overused and underdeveloped in most stories. They just exist for no adequately explained reason. Now you may say this is nit picking, it’s fantasy what does it matter if they don’t have an explained origin?
I will have to, disrespectfully, disagree.
First, I have to clarify that the following discussion applies only to Hard Fantasy where the rules of the world are logical and internally consistent. In a Sword and Sorcery book, these arguments fall down a little bit, as the explanation of nearly everything is to scream “Because MAGIC!” making this kind of discussion somewhat impossible. But without any further ado, let’s get into it.
Dragons do not make sense in terms of evolution, as while there were some very large flying reptiles in our planets past they maxed out in terms of wingspan at 10m and often in fantasy dragons are the size of mountains. You can say this is due to fantasy having to scale everything up until it is ‘epic’ but while I can accept that for manmade structures and objects, it is a bit harder with animals. Why would they grow that large? The amount of food they would need to consume would be astounding and not feasible in any world. The usual defence is that reptiles only need a little bit of food to survive, but seeing as that’s due to their cold blood that explanation goes out the window with dragons who are hot blooded by their very nature.
There are some interesting discussions online about how a dragon could exist in the real world if we discount evolution, and they all seem to agree that flying for the larger dragons would be essentially impossible, and for the largest dragons, even walking would be impossible. Breathing fire is actually more believable then a mountain sized lizard flying. At least there’s some analogue for fire breathing in reality with the Bombardier Beetle doing something similar involving chemical reactions and boiling hot streams of acid.
Now finally let’s get to the issue of sustaining a dragon. Since we’ve established they’re not a cold-blooded creature we can throw out the daily food intake of reptiles of around 1% of their body weight or less a day. Maybe we can use a large warm-blooded predator as an analogue instead. If we use a brown bear then a dragon would need to eat about 1/8th of its mass per day to survive. I hope you see the problem here. A dragon like the one we have been talking about, one of epic proportions would not be able to hunt down enough food ever day to live. I mean even if we err on the side of conservatism and say the dragon weights as much as a Blue Whale (which is overly generous when considering how large some fantasy dragons are said to be) then it would need to consume 17.5 tonnes of food a day. That comes to around 24 cows, or 150 sheep. That doesn’t seem to be a particularly achievable target. Not with how slow these animals would repopulate naturally and how if they were domesticated their owners would very quickly move on.
So the dragon can’t have evolved naturally, can’t support itself to walk, it can’t fly, and it would starve to death once it got to the classically ‘epic’ proportions fantasy books so love make them. On the upside, breathing fire is a possibility. One out of five isn’t too bad I suppose.
In the interest of fairness however, the next article on dragons will focus on how writers could get around these issues and still make them seem somewhat believable. If they’re believable then the readers more engaged, and the more interesting situations a writer can craft with them.