I just wanted to make my non-'Furry'ness absolutely clear. I do, however, have an odd liking for animal fantasy. I was just the right age - about 11 - to enjoy the Redwall series in its early heyday (I stopped after about the fifth or sixth book; there are now nineteen, apparently) and ever since then I've had a fondness for that weirdest of fantasy genres. I recently tried to reread the first Redwall book and couldn't get into it - it was written pre-Harry Potter, i.e. in the days when books for adolescents really were books for adolescents. But I think Duncton Wood has stood the test of time for grown-ups - being very dark and bloody, and very strange, as befits a book about sentient moles. (Give it a try before sniggering.)
Anyway, it seems that the Burning [X] crowd's newish game Mouse Guard has been set up to scratch that particular itch. It's apparently based on a comic (which as you might know I absolutely don't read - unless you're talking about Garfield, Dilbert, Asterix or Tintin). I'm not a big fan of the whole Burning Wheel thing, though I have flirted with the game and own its original iteration. I do however like the look of Mouse Guard, and might actually make a purchase - especially since this is specifically sold as a simplified version of BW.
Really though I'm not sure that there isn't anything about animal fantasy that couldn't be based on a free game like Risus or, heck, Swords & Wizardry. (I think I wrote recently about an idea for insectoid-animal-fantasy using S&W? I can't be bothered to find the post.) Really all you need is the suspension of disbelief and a willingness not to snigger, and to replace 'elf' and 'dwarf' and 'human' with things like 'mouse', 'rat' or 'otter'. A project worth thinking about, perhaps. We already have Ruins & Ronin and Fantasy Wild West. Why not Mice & Mazes? Lagomorphs & Labryinths? Hyraxes & Hydras? No takers?