Hmmm...
Well, there's Fly Like A Bird 3. You can play as a Crow, Pigeon, or Seagull.
There's really not much of a RP community there, and about 90% of the people that play are REALLY annoying, but if you gathered up a few good RPers from here or something maybe you could have a decent 3d RP in an uncrowded room. If you're looking for like canine and felines, though, you'll either have to use your imagination or just forget about it ._.
Oh, and one plus is that you don't have to download the game itself, but just a plugin if you don't have it already.