In the movie "How to Train Your Dragon," one of the most ferocious dragons -- known as the Monstrous Nightmare -- has a reputation for setting itself on fire and swallowing people whole. The lore surrounding this dragon specimen has deep roots in myths about the havoc that dragons can wreak upon humans.
Egyptians, for example, believed the dragonlike god Apepi ruled the underworld, and in the Bible, a seven-headed dragon symbolized sin [source: Encyclopedia Britannica]. Some Eastern civilizations associated dragons with power and self-preservation. In the West, dragons were believed to be dangerous and petulant creatures known for devouring entire herds of cattle and sheep, as well as the occasional villager. Dragons were such popular villains that they were inserted into contemporary settings in artwork and stories, a practice fueled by tall tales of dragon sightings.
A fresco completed around 1340 by an Italian painter depicts a chained dragon in the city of Rome. In 1366, the book "Travels" chronicled the journey of an English knight throughout the Middle East and references a number of dragon sightings. The English classic "Beowulf," written around 1000 A.D., features a dragon named Grendel [source: Ploeg].
There's also been some controversy about whether dragons could have actually existed as descendants of dinosaurs -- or whether finding dinosaur bones merely stoked our ancestors' imaginations. It's easy to see why the two could get mixed up, what with their shared terrible-lizard characteristics, even in the absence of tangible proof that any fossilized bones are actually from dragons. Dinosaur species found in China, like the Dilong paradoxus, often have the Mandarin term for dragon ("long") in their name [source: TVtropes.org]. And the culture's herbalists used to grind "dragon" bones for use in medical remedies. Modern scientists now believe the bones actually belonged to extinct animals like woolly mammoths, woolly rhinoceroses, and some species of Stegodon and Hipparion [source: Dharmananda].
Some believe the world's largest lizard, the Komodo dragon, is a descendant of dinosaurs -- and possibly dragons. Komodo dragons can grow up to 10 feet (3 meters) in length, and, although they don't breathe fire, they do have destructive tendencies, like attacking animals and humans with their sharp teeth and claws.
Actual fire-breathing dragons may not be spotted with the same kind of frequency anymore, but they still have a role to play as symbols and myths in modern society. Case in point? A dragon currently appears on the Prince of Wales' coat of arms and on the Welsh flag, where it symbolizes the military battles fought while the area was under Roman rule [source: BBC, Prince of Wales]. Read more about what dragons have been said to symbolize on the next page.