system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Who decided what creatures where magical and not muggle?

So when the Wizards and muggles war split the world's and the Wizards went into hiding, how did they decide what creatures should be hidden as magical? Before they split dragons would have just been dragons, not magical dragons?
gpt
Magic isn't a subjective judgement in the Harry Potter verse: it's a concrete force that can be detected and studied. Dragons were always magical dragons, because they used magic.

The boring answer is the magical creatures are the ones that are magical. It's no more subjective then if we listed all the flying animals. Magical creatures are the ones who can use magic, and muggle creatures are the one that can't.