One thing is clear: we all know that if they talk about zombies they mean a reanimated corpse. The one who established the standard characteristics of this type of creature was George A. Romero, the director of the mythical Night of the Living Dead, initiator of this subgenre of horror movies with a high content of blood and viscera. According to Kim Paffenroth, scholar of religions and author of the book The Gospel of the Living Dead, there are three: they can be killed with a shot to the head; they are usually slow, mentally and physically, but what they lose in speed they gain in strength; They eat people and the one they bite turns into a zombie.
The latter turns out to be a fundamental detail to understand its expansion in an apocalyptic world: contagion via bite. This limits the writers when looking for the possible origin of the epidemic: a bacterium or a virus, as in Malnazidos . The curious thing is that in none of them is a molecule similar to a prion, a protein that rose to fame for being responsible for the famous mad cow disease or Creutzfeldt-Jakob (CJD), considered as the source of the “disease”. Prions produce diseases that affect the Central Nervous System, a basic characteristic of zombie infection. Furthermore, this rare disease shares many of its symptoms with those of the living dead: in the early stages, CJD sufferers suffer from memory lapses, behavioral changes, lack of coordination, and visual disturbances. As it progresses, mental deterioration becomes more pronounced and involuntary movements, blindness, weakness of the limbs, and coma may occur, culminating in the patient’s death.
That the dead and buried come back to life is something biologically impossible. For this reason, in films like Malnazidos , death and conversion is a process directed by the virus itself, in this case as a product of Nazi experimentation. As if it were a game of scientific speculation, we can try to imagine how it could happen.
Everything must start with a massive attack on the vital organs. The jaundice that makeup experts so eagerly highlight can be explained as liver damage. It is possible that this organ, along with the kidneys ( zombies don’t pee, at least on screen ), is one of the first targets of the virus. On the other hand, and following the standards of the movies of the genre, the infection reduces the body temperature and leads the body to hypothermia. The heart drastically lowers the rhythm of its beats, which leads to a poor irrigation of the brain and the death of a large part of the brain mass, essential to eliminate the consciousness of the host and that the virus can take control of the organism.
But as we delve into the biological characteristics of the zombie, things get harder to explain. For example, your circulatory system. When you shoot them they don’t bleed or at most they spit out a kind of very viscous black liquid (fans call it zombie oil). This means that your heart is not pumping and therefore the veins are not delivering food and oxygen to the cells. This situation is unsustainable. The heart must work to maintain the minimal structure that a living dead seems to have, although we could grant that the classic 60-70 beats per minute of the normal human being were not necessary. To resolve the paradox, some hobbyists posit that zombie blood could be pumped by skeletal muscles. But, of course, that implies some kind of unknown mechanism. Another possibility is that the way our body feeds the cornea of the eye, which has no capillaries, appears on a large scale. Thus, the tear and the aqueous humor are in charge of satisfying their oxygen needs. Could this resource be used by future writers of this type of film? No, because the force of gravity plays against it. The blood that goes down to the feet there is no way to pump it to the head. The result would be that the poor zombie would leak blood like an old car leaks oil. Something that would not be too serious, as it is well known that zombies perfectly withstand large blood losses.
The biological problems facing a Malnazidos -type undead are insurmountable. Not eating food continuously (except for the few times when they have fresh meat within their reach) implies that they lack the homeostasis that characterizes all biological systems, absolutely necessary to maintain a stable and constant condition. Although they seem to be able to go a long time without eating, a zombie’s ultimate fate must be death by starvation , which is the clever way to kill off the infection they use in the movie 28 days later. Without a regular diet, the undead first burn their own body fat and then muscle protein… All this has a global effect that is not seen in the movies: over time a zombie must lose its ability to move . Luckily for Malnazidos, it all happens in three days…
That as long as it reaches this state. The practical inexistence of a minimum metabolism leaves the zombie in what it really is: a dead body, and therefore, in the process of decomposition. This makes it an ideal shelter for all kinds of insects and necrophagous microbes. In this sense, it is incomprehensible that no film mentions what would be his most characteristic hallmark of a living dead: his disgusting smell, product of substances with names as colorful as putrescine or cadaverine. Infections in open wounds and sores or their inability to stay warm in sub-zero conditions, for example, make it quite an achievement that they can live a year.
On the other hand, the destruction of the brain by the virus has a devastating effect on the sensory organs, such as the disappearance of the visual and auditory systems, to which should be added the development of myopia and color blindness due to degradation Of the eye. The only thing left to the undead is his sense of smell, only if he keeps intact, among other brain areas, the amygdala (a part of the brain that is also related to the storage of emotional memories). This would explain why they do not attack each other or devour each other: zombies must “smell” death and, therefore, identify its meat as unpleasant. However, it is peculiar that in fights involving a large number of zombies, no one attacks another by mistake: there are no casualties due to friendly fire. In the opinion of the writers, it is not very attractive that zombies attack each other. It is understandable: that would give the protagonists an opportunity, and that cannot be allowed.
