Questions like How did the roar evolve from snort?
There is communication and ethology, which are both relevant for all questions dealing with different forms of animal communication. Maybe we also need a more specific animal-communication (or zoosemiotics). For a tag dealing with auditory animal communication I would prefer animal-vocalization (or just vocalization). Some sort of vocalization tag would probably be usefuls to also deal with physiological issues/adaptations for animal vocalization. I don't like sounds, since it's very vague and could be used for widely different purposes.