A significant number of dragons think that once humans have lived for about a century, their ears become pointy and they call themselves "elves." This is the result of most dragons having extremely limited interaction with non-dragons. Those that have interacted with other species noticed that those with round ears were less than 100 years old, and those with pointy ears were over 100 years old. Given that "humans" and "elves" looked almost the same apart from their ears, the dragons just assumed that the humanoids' ears grew larger and pointier with age, mirroring their own horns. Thinking that this must be incredibly obvious to the humanoids, the dragons didn't bother to explain this assumption to them until it had already become common knowledge, and they were confused by the fact that humans didn't expect to eventually become elves.