Maybe it's too late but i've just seen this and can recommend a game called Lif. It's made by the creators of fly like a bird 1,2 & 3 and it's the same thing except, you don't play as birds and not in a city either. You can be several animals in the same game. A rabbit, a deer, a fox, a wolf and a bear. All animals are in the same place and you can mate and attack. It's 3D but i don't know if the graphics are good or not since i don't really judge by that. No download needed. You can change into any animal, anytime (if you find the totem for it). I hope this helps.