Re: Extinction, Relocation, or a possibly null and void
Yay! One of the topics I love to discuss:
The following is based on a this-dimension earth. Parallel earths may be different, and may allow for other things, but all we have to go on currently is this one.
I will say first off that I also really dislike relying on legends. The human mind IS perfectly capable of making things up, or seeing fossils and thinking they looked like something because they don't know squat about basic anatomy.
I equally have yet to see anyone come through with claims of magic that can have large scale affects on the physical world. Thus.
Dragons: The potential for a physically real, earth-native creature
We run into our first problem immediately. Nowhere else on earth, currently extant or in the fossil record, do we find fully functional 6 limbed vertebrates. If dragons came from earth, they'd have *evolved* on earth. For something that supposedly diverse, we should have found fossils leading up to and including dragons.
Second is size issues. Earth follows certain logical rules concerning weight and wing-surface area. The largest flying creatures to have ever existed on this planet were the Questzalcoatlus pterosaur (40ft wingspan, 200lbs max) and the Giant Teratorn (25ft wingspan, 200lbs max. Flapping flight more efficient.) So... both these fliers averaged about 150lbs, with a max estimate of 200lbs.
Let's look at other creatures that weigh 200lbs. These would be things like... mastiffs. large kangaroos... Now, the average "dragon" we see in the community seems to be between 20 and 40 feet long. There is NO WAY a creature like that could use manual flight because the bones of a wing long enough would be unable to support the massive body weight. A thing that a lot of dragons seem to forget is that tails and wings+flight muscles are HEAVY. ;_; So thus, two marks big marks against most "I'm from this planet!" dragons.
There are other lesser ones that go into my anatomy pet peeves, but I'll leave those alone for the moment.
Here is how I think the dragons of earth legend came to be:
One: Otherkin or people spiritually aware who could have seen spiritual dragons.
Two: Fossils. Look at pterosaurs. They're pretty much a perfect fit for the idea of wyverns. And anyone who's played the telephone game can understand how easily a sentence of "It's arms were also wings" can turn into "it had arms and also wings". Thus we have the hexapodals.
Three: Extant creature conglomerations. Cyclops from elephant skulls. Eastern dragons from carp and crocodiles (just look at them!). Heck, many pictures of 'dragons' from europe look like funny crocodiles. Remember, these are the people who managed to turn *rhinos* into delicate deer-creatures.