That line is actually a line from my step-mom, who told my dad this in a restaurant, where we were having X-mas dinner!
We were sitting in this exclusive restaurant, all dressed up, invited with only a few families on X-mas day, and were waiting for the 2nd course to arrive. They served salad with it, and my dad said: "Hmprf, I'm not a bunny" and she fired that one at him. I remembered it all these years (She sadly passed away shortly after). It's an homage to her, really.