I know I make fun of Pliny the Elder a lot, but I genuinely can’t stop thinking about this approach to taxonomy:

[There is a fish called the tursio, which bears a strong resemblance to the dolphin; it differs from it, however, in a certain air of sadness, and is wanting in its peculiar vivacity.]

Like, imagine someone describing an animal to you, but the only information they’ll provide is that it’s sort of like another animal, but much much sadder.