What skill check should be used to hide your race in pathfinder?

I have a character who is a non-standard race, and he doesn’t want people to know what he is.

I’ve read the disguise rules but they only seem to apply for trying to look like something specific, and not for hiding aspects of your appearance. I also couldn’t find anything in particular about identifying particular aspects of a creature’s appearance under clothing.

If my character wants to hide his race (like by wearing full body clothes and a mask), would he be rolling disguise opposed by perception or something else, like sleight of hand, performance, etc. opposed by, say, perception, or just a standard knowledge check by the opposing party?