Considering the origination of said infestation, I believe the roots of the creature might need be explored a bit. I thought I would post a bit of my own research to aid in this...
zom•bie
Pronunciation: (zom'bE),
—n.
1. (in voodoo)
a. the body of a dead person given the semblance of life, but mute and will-less, by a supernatural force, usually for some evil purpose.
b. the supernatural force itself.
2. Informal.
a. a person whose behavior or responses are wooden, listless, or seemingly rote; automaton.
b. an eccentric or peculiar person.
3. a snake god worshiped in West Indian and Brazilian religious practices of African origin.
4. a tall drink made typically with several kinds of rum, citrus juice, and often apricot liqueur.
5. Canadian Slang.an army conscript assigned to home defense during World War II.
In accordance with available information, I believe we can narrow zombies into eight categories:
1.) Toxic Zombies
Brought back by radiation, biological agents, or chemicals; usually flesh-eating,
this is by far the most common type of zombie portrayed in films. Quite often the government has something to do with the 'birth' of these. Watch out for Army trucks with barrels on the back going through your town!
2.) Demon Zombies
Reanimated by demon, devil or other evil spirit.
3.) Voodoo/Black Magic Zombies
Brought back by a houngan or bokor (a voodoo master).
4.) Diseased Zombies
Vague type spread by infection, such as by the bite of the Sumatran rat monkey.
5.) Unsettled Zombies
Return because of some unfinished business of some sort, usually revenge or love.
6.) Alien Zombies
Brought back by aliens; usually to serve them as an aid in taking over the Earth.
7.) Techno Zombies
Reanimated by technology; implanting a computer chip in the brain, etc.
8.) Electric Zombies
Brought back by a shock from electricity of some sort.
Now obviously, there are some options more realistic than others, but it never hurts to be prepared for any eventuality.
Known Behavioral Characteristics- Zombies primarily crave human flesh.
- They will consume living or freshly killed bodies.
- Zombies have also been known to consume other living organisms although this is irregular.
- Zombies appear to be able to discern the difference between another zombie and a living human based on sight only.
- Zombies will not attack each other although they have been known to fight over food.
- Zombies often frequent places they are familiar with from their normal life.
- Zombies may be quite weak in the initial stages of reanimation. In Night and Dawn, generally people could run in amongst them without much danger.
- They seem to increase in strength over time. By Day of the Dead, people are not so capable of breaking free from them once a zombie has hold of you. They are also capable of tearing apart a human being with apparent ease. In Day of the Dead, the zombies were strong enough to tear a man in half and tear a man's head off.
- Zombies retain some knowledge or memories from past lives.
- A dead body will rise within a few hours unless the brain is destroyed.
- Zombies appear largely incapable of normal speech. Some specimens have retained very rudimentary ability in this area.
- Some zombies appear to be capable of simple reasoning or have a limited intellectual capacity.
Zombie PhysiologyThe next step is to analyze in more detail the aspects of their physiology. This information was either stated in the movie or can be determined based on observation. - A zombie must have the brain damaged by an exterior source in order to terminate its existence.
- The reanimation only seems to affect humans.
- The bodies remain animated for a period of up to 10 years before decay threatens the mobility of the limbs.
- The normal decay process is drastically slowed down or inhibited.
- Fluid levels within the organism appear to be maintained, otherwise the animated corpse would simply dry up and be unable to function. Yet we never see a zombie drinking water or liquid, except through the consumption of food.
- A zombie does not require food for sustenance. A zombie with all its internal organs removed will continue to function. It has not been indicated to what extent the removal/damage of the internal organs will affect the longevity of the reanimated person.
- A zombie can also function without the normal flow of blood, since it has been remarked that the heart stops beating. This critical fact means that cells are not supplied with nutrients and fluid in the normal manner. Yet the cell structure seems to remain intact over a period of years.
- I do not think there is any evidence to conclusively support the notion that a zombie bite alone will cause reanimation. A zombie bite may cause death in a human. But the body itself may become reanimated for the same reason that bodies became reanimated in the first place (disease/radiation/etc).
- Reanimation may not necessarily be caused directly by a zombie bite. Alternatively it may be observed that an uninfected human rarely survives a bite.
Explanation for ReanimationBefore continuing, it may be important to discuss the source of the reanimation, since this may give us some insights into what causes the zombies to function. Note that in the original Night, speculation centered on the destruction by NASA of one of its probes to Venus. The probe was found to be carrying a strange radiation with it, and this may be the likely cause for reanimation. However we must not rule out other possibilities. The potential causes for reanimation are:
- An alien virus that came to this planet from outer space (via meteorite/comet/NASA).
- A man-made virus created in a laboratory that perhaps mutated and was accidentally released.
- An attempt at biological warfare that went drastically wrong.
- A large-scale radioactive or chemical leakage.
- Judgment Day - punishment by God - theological reasons.
The question then becomes: how do the zombies function? What allows them to defy the laws of nature by remaining animated and mobile for so long without decaying? What causes them to desire human flesh?
For those who are inclined to take the religious explanation, this pretty much rules out trying to come up with an explanation for any of these, since applying a logical explanation to theological forces is a futile argument. The zombies were sent as a punishment for man. Or perhaps the concept that hell had reached is limits may prove to be correct.
For those less inclined to take a theological reason, the most likely possibility for reanimation would be an alien virus. The effects were noticed on a global scale and in a short amount of time. This means the virus would have been spread through the atmosphere initially, rather than by a host organism, such as occurred with the black plague.
The virus mostly likely altered cell structure in a manner that counteracted decay, as well as increasing longevity without the normal requirements of air, water and energy. The reanimated corpse would then have initiated some form of overall operation, at both the cellular level, and at the higher levels. The driving force is still clearly the brain, which continues to operate in a semi-normal manner. Signals for coordination and mobility were still being issued from the brain via the nerves, and implemented by the muscles.
Why Do Zombies Crave Human Flesh?This is the most difficult question of all if we ignore a theological explanation.
It is one thing to accept that an alien virus can adjust cell structure and affect a human being such that it causes reanimation with altered functionality. But why then does the zombie itself desire to eat human flesh? Something most humans would never consider in normal life?
The infected brain clearly has some processing and reasoning capability. Perhaps each zombie reverts to a basic carnivorous nature and simply desires to consume any living creature. Although never indicated to any extent in the films, it is highly likely that a zombie would attack any living creature within the vicinity, including domestic and wild animals. It is not specifically targetting human prey.
However in the initial stages of zombie infiltration, where zombies were reanimating in the midst of normal society and in populated areas, human prey just happened to be the most abundant. And the zombie itself, with its limited reasoning power, may simply associate another human as the highest candidate for prey, since they associated mostly with others humans during their life prior to reanimation.
Please feel free to add to this if it looks like I may have overlooked something.