Faunus are usually mammal variations, but I could be mistaken.

Well, if we want to be technical, and we see a female avian/reptilian/aquatic Faunus with boobs, then all Faunus, regardless of their animal trait, is a mammal and thus have belly buttons 'cause fuck the Platypus. Not really. They're an awesome variation of abnormal mammal.

EDIT: Starcraft II's Arcade is free, so, like the days I've played WC3 24/7, I'm going to bury myself in that game. Until the timeskip, that is... *Cough*