This is Bob. Bob is my zombie pet. My zombie pet is eating a lollipop. Good zombie pet. No human brains for you mister. Because that is bad behavior. Humans don't like to get their brains eaten. How would you feel if someone nomed on your brain? Not very good, huh. Even if you are a zombie, you would die. I am insane.
Kolumbo
Well he did get his brain eaten since he is a zombie...
iRocker (Updated )
Or he could have gotten bitten elsewhere since zombies cannot survive without a brain. Hence, the whole bullet to the head theory.