YOU ONLY LIVE ONCE...MAYBE TWICE!
We need to ask a few questions that seem to slip the minds of writers and fans everywhere! How do dead things moan when they aren't breathing? You cannot ingest flesh without expansion. What happens to the consumed material? Movement still takes energy which is provided by consuming calories which need to be "burned" by mixing with oxygen. How do the dead accomplish this without breathing and circulation? Nix to virus caused zombification because a virus needs a "living" host to survive.
Unless the zombies aren't really dead. Check David Wellington's cool "Monster City, Nation, Planet" series for one possibility.
Laws of Physics are laws for a reason. This is why I laugh my ass off every time Sam on True Blood changes from himself into a fly! That must be one heavy fly! Too heavy a fly to fly even! Shape shifting of any type requires so much energy that feeding demands would out weigh any other needs! More over, life expectancies would be incredibly short due to stresses on bones and organs. Vampires of course are so ridiculous to consider because their energy needs cannot possibly be met by consuming blood, which is primarily water. The only possibility is if these creatures are truly supernatural in the sense of God and Satan.
Sorry, my mind wanders sometimes. Too many long nights in the fields of pain!
So, if anyone has ideas concerning why zombies (ghouls actually) do what they do, please share them with me. I am writing a novel and am tackling just these issues. Might not be much of a novel if it is all scientific
Thanks for your time.