It’s a common misconception that dragons are reptiles. The are actually mammals. For some reason, historical depictions of dragons depict them with scales—this is inaccurate, real dragons have fur, give live birth, and even produce milk. I think the misconception of dragons as reptilian has an origin in early European depictions of dragons. Dragons are not native to most parts of Europe so we can assume that the artists never saw a real dragon. You can see similar inaccuracies in depictions of other animals, like lions, leopards, beavers, and elephants.

You’d think the Unicode consortium would know better. Dinosaurs are also miscategorized as reptilian but I can understand the mistake, because dinosaurs are extinct.