It is a man thing. The wolf is a symbol of male dominance. ie. the wolf stare. If you wear the "thee wolf howling at the moon shirt" it means you are super dominant.
Animal roleplay may be either a non-sexual or an erotic sexual role-play (when it may also be called petplay, ponyplay, ponyism, kittenplay, or pup-play). In its erotic sexual role-play form, one or more of the participants takes on the role of a real or imaginary animal in character, including appropriate mannerisms and behavior, and sometimes a partner will act as another animal, or, in a sexual context, may take the role of rider, trainer, or caretaker (or even breeding partner).