A while ago, a fellow artist and I got into a lengthy debate about dragons and how they would perform realistically in a medieval fantasy setting where they were the only fantastic entity to exist.
MANY personal insults were exchanged. >_>
But beneath it all, we rarely debated exactly what the dragons were. We did both agree on one thing: pterosaurs make a good starting point.
So, in the interests of critical thinking, I got to work on creating a hypothetical form that dragons would take in these debates. Naturally, I started with a pterosaur and went from there.
Our creature in question has a wingspan of about sixty feet of thick, multi-layered flesh, transforming their entire bodies into flying machines. Each wing sports two elongated fingers rather than one, increasing the malleability of the structure and making the creature far more agile in the air.
Its brain is large, thus necessitating the heavy crests and plates that would eventually become symbols of dragonhood.
Because of their enormous food requirements, they usually swallow their prey whole, and can in fact, become heavily weighed down by their meals. Their bodies digest almost all of what they take in, and in some cases, have even assimilated metals into their scales(this tends to further impede their flying abilities, and some older individuals have lost the capability entirely).
A gastric biproduct of their digestive systems is regularly expelled orally and has been known to ignite under the right circumstances, producing a burst of flame. Dragons primarily use this in threat displays, as it's rarely a reliable weapon. More often, the gas is sprayed into the faces of adversaries, burning their eyes and leaving them vulnerable.
They're sapient, but their minds differ from our own. Dragons are, by default, selfish and isolationist, lacking any instinct to herd or raise their young, as other dragons meancompetition for food. They think nothing of cannibalizing their own if the opportunity presents itself.
By the late Cretaceous, large pterosaurs had all but deposed mid-sized theropods on the food chain. In this scenario, some species managed to outlive their dinosaur cousins and continued to evolve even as man came onto the scene.
As climactic conditions changed, intelligence soon became beneficial as the creatures were forced to get creative about their survival. Before long, their brains had become comparable to those of primates and corvids, their skulls developing large, thick plates to protect them. Though their intelligence was great, their bodies, against all odds, remained huge. It remained prudent for them to keep their distance from one another, or risk overhunting their territories.
As man came into being, they found bitter enemies of the dragons, first as prey, then as competitors. A single dragon was enough to challenge an entire tribe, and as their enmity grew, it became difficult for humans to sow crops without them being defiled by the beasts. Man, in turn, soon wised up to the dragons' greatest vulnerabilities and began destroying their own environments, slaying as much game as possible, gorging on what they could and wasting what remained. Famine did ensue, as did considerable retaliation from the reptilian lords of the air.
As eons wore by, man and dragonkind turned entire continents into battlegrounds, entire tribes destroying one another. But eventually, where the dragons starved and fell, man hunkered down and fed on the fruits of their lands that were too small to sustain the giants. In time, man came ahead and dragons faced extinction. They became beasts of legend, feared as things that could challenge dozens of men at once, but seldom seen.
Rivalries of the ancient days were forgotten, but new ones formed. They were hunted by entire platoons, and in return, left entire villages in ruin, starving and devouring those not protected by the walls of their kings and queens.
However, mankind proved all too accustomed to death. Not a century after the invention of gunpowder, the dragons were no more.