Monika's comment - which I completely agree with, btw - made me think... technically we are animals, aren't we? We're just very highly evolved, with the ability to think abstract thought, know the concept of right from wrong, etc. (Unfortunately, some people still act like the unevolved animals that they came from millions of years ago, but that's a whole other discussion.)
If anyone ever made that comment to me I might just say something smart-alecky, like, "Well, what are you? A car?" (is that too much?)