A general "animal_girl" tag would get more use.
We use "fox", "cat", and "dog" because those are the three most popular and generic types of "beast" girls in the anime world. We do not tag for other types of animals, and we do not tag for things like dragon girls or girls representing other mythical beasts or insects or non mammals. "Animal ears" and "tail" and even "wings" are meant to incorporate every type of anime girl based on any type of animal or beast. There is also a pool specifically meant for girls (or guys) who are partially animal. This includes (but is not limited to) things like lamias, centaurs, and spider women.

Point is it's just not sustainable to go and make a tag for every type of animal girl. I get that there's an anime out now with horse girls, but if someone were interested in that they'd be able to find what they were looking for without the need for a general tag.
otaku_emmy said:
And as far as that goes, someone looking for specifically those characters need only click the tag for the anime.
Fair enough.

Senakysam said:
A general "animal_girl" tag would get more use.
No, the work for tagging every girl that would fall under that tag would be hideous.
When you think about it, the actual anime title has "horse girl" in it. :p