Here is a question that I think is a bit related to this.
I guess to keep it short .. at what point does one become a fur? Is a fursona required?
I'm no expert but I would say the combination of an interest in anthro animal characters plus self identifying as furry does it. Everything else is just layers. A fursona is a very common initial opting in point but some people are intimidated by the range of possible choices.
So if that was the case, then someone who may like furs and may have a fursona but doesn't always identify themselves by that fursona wouldn't be a fur? That self identifying part always confuses me. I have a fursona .. a rabbit .. and I would identify myself using that fursona but at the same time I would identify using other persona's such as the one in my avatar.
lol what can I say .. I am just a very confusing person. XD
By self-identifying as a furry, I mean it as simply as being able to truthfully say "I'm a furry." You're free to have other interests and personas or multiple fursonas if you wish, or none.
Like I say, I'm no expert but I skirted around the edges of the fandom for a good while, and this is the only definition that makes sense to me.