system
Given the following post, respond as if you're commenting on Reddit:
human
[Anime in general] So, do catgirls have two sets of ear canals? Or is one set of ears vestigial?

I mean, they mostly DO seem to have human ears, where a human's ears should be, when they're not hidden by hair. So do they have double hearing, and the top of their skull accommodates another set of fully-functioning ear canals?
gpt
Generally, when they hear, the upper ears turn and react, and they tend to mostly interact with them. You don't really see one, say, uncovering their ears to hear better.

This implies the upper ears are their *actual* ears, and the human ears are vestigial remnants of their human ancestry. Like our tailbone but more obvious.