Dragons are great monsters of fairytales and myth but, like a lot of myths, there does seem to be some truth to their existence. Originally great skeletons of dinosaurs were thought to be the remains of dragons but the bones of such flying dinosaurs as the Pterodactyl (pictured on the right) may have been an inspiration for dragon stories. The great scaled body and sharp forked tongue of dragons is present in the Megalania Prisca (Ancient Giant Butcher in Latin) which was a great lizard growing up to 30 feet long (longer than a bus) and capable of attacking and killing creatures even bigger than itself. This great beast became extinct thousands of years ago however and our closest links to dragons in modern day are found in South America, Indonesia and the sea.
Indonesia is home to the Komodo dragon, a great muscled, strong lizard with a forked tongue and poison saliva that can be as tall as two adult humans combined. They are the largest living lizards in the modern world and have been known to attack humans in some rural (countryside) parts of Indonesia. Their acidic saliva (spit) means that when they eat some of their prey the remnants appear burnt as though by fire. Therefore Komodo Dragons would be a likely explanation for the orgins of dragon myths in Medieval Europe except that they were not discovered by Europeans until 1910, some 400 years after the end of the middle ages. Australia's frilled dragon is a smaller creature but has a large frill around its neck that it raises in defense and is a very scary looking creature. This animal is less of a threat than the Komodo but is still terrifying to look at and descended directly from the dinosaurs with it's frill neck this creature may confirm that flying dinosaurs are in fact the inspiration behind dragon legends.
The European Dragons were likely a mix of legend, the discovery of dinosaur bones and the desire to create scary stories, but the Dragon tales of China and Asia may have more credit to them. In Asia dragons are depicted largely as amphibious creatures (able to live on land and in water) and considering the number of great reptiles in Asia that fit this description such as the many breeds of Alligator and the Sea Dragon there may be more truth than with the European flying dragons. Though flying dragons are seen in Chinese lore they are considered spirits and guardians rather than physical animals on this Earth. The Sea Dragon, ultimately a scarier looking sea horse, (pictured on the left) may contribute somewhat to the tales of beasts in the water and great Alligators and Crocodiles which descend directly from dinosaurs may also inspire tales of great amphibious serpents. The world as a whole is undecided on what a dragon is and what they look like but there are many combinations of animals both extinct and current that could explain the myth of dragons.