For the ”dead zombie”, I think the most plausible scenario has already been stated above: a form of hive-mind unicellular creatures. Such a creature could simply use the already present structures of the human body but alter their functioning. Imagine that those creatures could produce energy from eaten flesh by themselves and distribute it throughout the body through some kind of ”osmosis”, that would eliminate the need for a pulse and respiration. The non-necessary organs would rot and the host would be dead but there would be a new life form inhabiting the body, maintaining the shape and the functions that serve the hive.

Considering all those factors in favor of a possible zombie apocalypse, I would suggest you start packing food, water and ammo if you know what’s best for you and your family.

There’s a whole monster CLASS SYSTEM. Vampires are old-style aristocrats (and worshiping them makes their fans true traitors), while zombies are the proletariat. So who’s the MIDDLE CLASS?

Well, it used to be lycanthropes, werewolves. Poor schlumps in the suburbs, the only monsters with families,mortgages to pay and lawns that need mowing. Their affliction is portrayed with sympathy and angst and made for INTERESTING stories! Their new powers and temptations conflicting with bourgeois values, leading to inevitable tragedy…

…except in the wonderfully up-beat and American TEEN WOLF.

and except for the recent UTTER BETRAYAL of the whole idea behind wolfmen, in these awful new series that portray “lycans” as just another kind of arrogant asshole monster race preying on normal people, completely missing the point of what they are about!

David Brin… author of The Postman and Earth

If the process of decomposition has already begun, the zombie does not have much time before the host body becomes unreliable. Evolution simply would never give such a risky system good odds.

Zombie flicks always focus on the persons fighting the hordes, but never on the zombies themselves. What happens to the zombies that don’t find anyone to infect..or even if they do, what happens to them over the long haul? I think they themselves would re-die in a matter of days as the functions fail so much that even the virus cannot sustain it.

However, viruses usually never infect someone “for keeps”..they infect to use the host to reproduce, and their offspring go on to infect others and so forth keeping the species of virus alive but sacrificing the infecting viruses in the process. I think zombies hunt humans not to get sustinance, but to simply spread the virus.

1) The mold “needs” (hand wave) neural tissue, which leads to the impulse zombies have to eat brains. Anything with neural tissue gets targeted.

There are different strains; each strain “prefers” non-infected flesh but will also try to take over flesh infected by a different strain.

The body stops “living” as a human and becomes a mold host; the mold takes over life functions.

2) There are two phases of the main strains: mobile and spore. The mobile (zombie) form lasts only so long (hand wave) and then becomes a puff ball of spores.

The mobile zombies can use mold to reattach body parts, although it isn’t pretty or structurally strong.

The other strains have a third phase related to the alien genetics; I won’t say anything further about it here.

3) Mobile zombies spread contagion via contact and fluid; spores are spores and thus even nastier.

I wanted to achieve three things:

1) A world in which people had to compete with another life form, a massive change.

2) A world in which the most powerful weapons were bleach and alcohol.

2) Brains that taste better than truffles. (It’s a comedy.)

@Idlewilde: That’ll teach Dave to generalize. My guess, with your question about amputation, is that a person would only have a few minutes to amputate if bitten in an extremity. This is all made up, but with some venom (like black widow) the poison does far more damage in the heart than in the extremities. I guess it would depend on blood flow up the arm and point of entry. But, yes, if you amputated in time the person would be ok.

One question: If a guy who was bitten by a zombie got his bitten arm amputated directly afterward, would the virus not have had time to spread? Would he survive, all risks of amputation aside?

How much of the brain, and what level of complexity, must be preserved to enable zombie behavior? If the pathogen must provide nutrient secretions, a pre-existing fungal infection also seems to fit the bill.

Lastly, should we assume that zombies actually process the flesh they eat and gain sustenance from it? Day of the Dead, the third film in Romero’s classic series, establishes that the zombies are compelled (programmed?) to eat flesh, but don’t derive any nutrition or benefit from it. In the case of a pathogen (in Night of the Living Dead, the cause of the zombie outbreak is presumed to be unusual radiation brought to earth by a space probe), the cannibal behavior can be explained as a reproductive strategy: exploiting the existing bodies of humans and their instinctual urges to eat.