by Tedd Roberts
We've seen it on the screen or in our mind's eye – the ravening hordes, the animalistic sounds, the hunger that cannot be sated – zombies! I was recently on a panel at a science fiction convention that discussed the transition from prior popularity of vampire stories to the current fascination with zombies. The moderator put forth the premise that vampire novels and urban fantasy are products of affluent societies with strong economies, while zombie novels and apocalyptic fiction are more representative of economic downturn and uncertainty. It is an interesting premise, given that the "classical vampire" is hundreds of years old, has amassed wealth, power and prestige... while zombies represent death and destruction that cannot be stopped by conventional means.
If I were a psychologist, I might mention that zombies represent fear of "The Other" - the foreign, even alien, presence that steals away our home and family; or that zombies represent fear of death or ending. On the other hand, as a firearm collector, Eagle Scout and member of Zombie Squad, I would bring up the fact that preparation for The Zombie Apocalypse is preparation for any disaster: natural or man-made. It only makes sense that a story-line which involves preparing to defend against the loss of all we hold dear would be popular in uncertain times that threaten jobs, homes and our very lives.
Whatever the appeal, zombies and the zombie apocalypse are prevalent in modern fiction—from Max Brooks' World War Z (and the movie of the same name, but derivative story) to the popular TV show The Walking Dead. The modern zombie story/zombie movie genre owes a lot to George Romero's Night of the Living Dead—but it can easily be argued that Mary Shelley's Frankenstein founded the concept of the metaphysically reanimated corpse. In Baen's own fiction, Larry Corriea's Monster Hunter International novels invoke (and dispatch) zombies by the hundreds and thousands. In fact, the image of seasoned Monster Hunter Earl Harbinger chopping and puréeing zombies through use of industrial snow-clearing machinery has led to a popular convention panel "Messiest Ways to Kill Zombies." The launch of a new Baen series – and the motivation for this post – is John Ringo's upcoming Under a Graveyard Sky, which follows a family escaping a zombie apocalypse and dealing with the aftermath.
It is notable that many present day zombie stories (Monster Hunter excepted) have departed from the Haitian voodoo concept of magical reanimated corpses and skeletons. Instead, the modern zombie story often focuses on a bacterial or viral source of infection, and that infection can either reanimate a corpse, or transform a living human into a ravenous, brainless creature. Such is the premise of Ringo's Under a Graveyard Sky, and we'll explore theories that could provide a scientific basis for zombies as we progress through this article. However, first we'll set the stage by looking at different types of zombies as represented in science fiction and fantasy.
Zombie History—a Taxonomy of Zombies in Fiction
In movies and novels, zombies are either mindless horde animated by evil magic, or "animalistic sub-humans created by evil technology." They may attack under funny circumstances, as in Bruce Campbell movies or the campy classic Shaun of the Dead. On the other hand, the zombies may be coming at you in an unstoppable or as in The Night of the Living Dead. Anyway you look at it; the zombies are the enemy and are out to get… you!
Zombies in TV film and literature fall into approximately four categories with some overlap between them:
Interestingly, the current pop-culture concept—insatiably hungry, killing machines—is a fairly recent development in literature and can largely be attributed to George Romero's Night of the Living Dead (1968). This movie clearly falls into Category One above. In this instance, the zombies are corpses which have been reanimated; however, there is a considerable element of the "ghoul"—a creature which may or may not be dead, but which inhabits graveyards and eats human flesh. In contrast, the classic movie monster, Frankenstein, is basically a zombie, in that it is composed of cadaver parts and animated by a mad scientist, but lacks the modern concepts of hunting and feeding on humans. Consider, for example, the humorous zombies of Piers Anthony's Xanth series: The Zombie Master is a human sorcerer who reanimates corpses as servants. The corpses are constantly losing parts, and present no real danger to humans, but only one individual can repair or even create zombies in the first place.
The hybrid crossover produced by Romero in Night of the Living Dead is very important to the more modern notion of a zombie craving brains or feeding off of human flesh. The "Resident Evil" video games and movies feature Category Two zombies which are dead humans brought back to life after being infected with a virus. Max Brooks's World War Z, and of course the "Infected" of Ringo's Under a Graveyard Sky are examples of Category Three, in which the victims of the mysterious virus first fall into a fever or coma and seemingly "recover" hours later, but as a mindless, virtually unkillable creatures (largely because they feel no pain, and are thus not stopped until they can no longer move. Likewise, Category Four zombies need not start out as corpses—they may be perfectly healthy humans prior to infestation—but the sentient, infesting agent such as The Flood in the game Halo, takes over the bodily functions and effectively kills the body and/or human consciousness. In many ways, Category 4 zombies are a variation of Category 3 except for the implication that rather than a virus, the infection is by a symbiote or parasite that has its own consciousness (e.g. Robert A. Heinlein's The Puppet Masters).
A feature of many zombie stories both in film and print is that the "zombie infection" is spread by a bite, causing crossover between different categories of zombies, as in the Will Smith movie I Am Legend in which it's not clear whether the zombies were precisely dead creatures reanimated or living creatures infected with the zombie virus. Of course there's always fun movies such as Bruce Campbell's Army of Darkness, which to be honest, is not really a zombie movie, since the primary creatures are reanimated skeletons (of the Ray Harryhausen Jason and the Argonauts style) and not corpses per se.
While it is not my intent to go into a full analysis of horror movie psychology, the essence of a zombie movie is to play on both fear of the unknown, and fear of that which cannot be (easily) killed. The basic concept of a zombie is a creature that can be hit, shot, sliced, or even set on fire, without stopping it. In Larry Correia's recent book Monster Hunter Alpha, the reader comes face-to-face with the rather infamous character Joe Buckley, who survives being shot, sliced and even blown up and still comes back to menace the protagonist not once but three times. The idea of a creature that can be run through with a sword, and still keep advancing means that most means of defense would not work. Hence the appeal of "preparing for a zombie apocalypse" implies preparing a defense that can deal with situations that are seemingly indefensible. Again, psychologically this plays into combating the helpless feeling of nightmares.
A discussion of zombie books and movies is not complete without discussing speed of zombies. The classic shambling (barely) animated dead—or shambler—is the most scientifically logical based on the idea that the an animated corpse has no source of energy, no way to recover from broken bones, amputations, and no mental facility. On the other hand, if one allows magic, the animation need not concern itself with such mundane matters (i.e. Harryhausen's animated skeletons). No, it is the fast zombies that are problematic—the ones in Zombieland which chase down their prey, or the "Ax-man" in Resident Evil: Extinction [Once you get to the horror-movie elements of the transformed creatures in Resident Evil, you're really not talking about zombies at all]. For a zombie to exhibit strength or speed, we must posit an energy source, and the most likely explanation is that the zombie virus or drug consumes the remaining tissues of the body. However, that is a discussion for later as we discuss zombie infection.
Zombie Origins – How to Create Zombies
So what makes a zombie (scientifically speaking)? In the particularly Haitian voodoo mythology, voodoo priests could turn living humans into mindless servants through their magic, which in reality consisted of a combination of pharmaceuticals, which suppressed higher thought functions. One of the chemicals used, traditionally, was tetrodotoxin or TTX. TTX is well known in neuroscience: it is a chemical which blocks sodium channels, preventing the depolarizing sodium entry into neurons necessary for the formation of an action potential. In the presence of tetrodotoxin, neurons are unable to receive and transmit the neural signals which underlie information processing of the brain. TTX is an extract from puffer fish, fish used in the risky Japanese dish known as fugu. Fugu is a dish for risk takers and adventurers. The chef must take great care not to break the poison gland, which contains the TTX, and would kill anyone who consumes the dish. On the other hand, just the smallest amount of TTX will cause a slight numbness to the tongue and lips and give the sensation of daring and risk to aficionados. A dosage high enough will block all nervous system and muscle activity, while moderate doses will block some brain activity, but not all. The use of neurotoxins is hardly unknown, considering that the neuromuscular blocker curare was first discovered in use by native tribes on their blowgun darts to disable large prey. So is not unheard of that primitive medicine and ritual may very well have developed the use of tetrodotoxin as a medicine for suppressing violent and aggressive behaviors. It is that only a small step from such use too much more serious case of deliberately suppressing higher mental function, leading to legends of the voodoo zombies who functioned as slaves for their evil masters.
On the other hand, there are a number of other possibilities from a scientific perspective for the classical "mindless, reanimated dead." Aside from the fantastical gimmick of magical reanimation, science fiction authors have toyed with the idea of zombies created by alien organisms, viruses, stem cells, and nanomachines. I mentioned the latter in a recent blog post, in conjunction with the web comic Schlock Mercenary. Science fiction author Larry Niven postulated an alien virus that could reanimate bodies of dead soldiers on battlefield. In the short story "Night on Mispec Moor" Niven's protagonist finds himself the only survivor as night falls after a brutal battle. Unable to leave the scene as the bodies of friends and enemies begin to reanimate, he seeks high ground where he can make his own defense, only to discover that his medical kit holds the secret to survival. Surmising that an alien virus or microorganism is reanimating the bodies, he sprays them with a broad spectrum antiviral/antibiotic, causing the bodies to collapse and return to the fully dead state. Robert A. Heinlein's The Puppet Masters provides a similar cautionary tale in which aliens are able to control the bodies of humans, whether those humans are in fact alive or dead.
Yet the most intriguing notion comes from recent studies with stem cells. As medical research increasingly looks to the possibilities of stem cell therapies for tissue regeneration and growth, one question that is often asked is what will happen if the stem cells begin to grow in a manner that was not planned for? While the most obvious result would be cancerous tissue, another possibility is that stem cells could result in a restoration of dead, necrotic tissue. If enough of this tissue is restored to a near living state, would this not make zombies? Still, the problem is one of reanimation of the brain tissue, but even that seems to be yielded to modern medical findings of patients "brought back to life" after many hours as long as the body and brain are kept very cold (but not frozen) and well oxygenated. We'll explore these consequences as a well of possibly explaining the mindlessness of zombies in the next section.
It is an interesting contradiction in fictional literature that zombies are essentially brainless, yet the only way to effectively defeat a zombie is to destroy the head and brain. Reanimation of neural tissue should require the ability to not just provide glucose, oxygen and other essential nutrients to the neural tissue, but also a way to restore the electrochemical activity. Perhaps it is most telling that what we think of as memory and personality is primarily the result of the synaptic connections that our neurons make with each other. Once an organism is killed, the once living cells undergo a process of necrosis. Essentially what that means for our zombies, is that the cells no longer have intact intracellular mechanisms, nor do they have the same connections between cells. If we extend this now to the brains of humans, we begin to understand the very soon after death the synaptic connections between neurons would break down. With the loss of synaptic connections, the knowledge, skills, memory, and personality of that human would also be lost. Thus, if we reanimate the body, the "mind" would still not be functioning. Nonetheless, control of the muscles which allow the zombie to moving walk would still reside in spinal cord and brain stem with some residual signal coming from the motor cortex.
Thus, the idea that zombies represent some form of reanimated corpse, necessarily brings with it the idea that brain function could or would not be restored, and reanimated corpses would be able to do little else than lurch and moan. On the other hand, transfer of pharmacological or infections agents could very well affect living humans to the point that they exhibit the same characteristics as the living dead.
Ringo's Under a Graveyard Sky will be in public circulation around the time this article is published, however, advanced reader copies have been out for a few months, and John has been publishing snippets of his writing for a few months before that. What I find most amazing about the early reader comments is all of the people who criticize the idea that "a mere infection" would result in the animalistic, primitive behavior of the Infected. Furthermore, this complaint typically takes the form of "nothing would change the behavior/personality so radically and not kill the subject." Really? I invite those same readers to investigate the case of Phineas Gage (http://www.smithsonianmag.com/history-archaeology/Phineas-Gage-Neurosciences-Most-Famous-Patient.html).
In 1848, railroad construction foreman Phineas Gage suffered an injury from a premature blasting powder explosion. An iron tamping rod more than an inch thick, was propelled by the explosion, striking Gage in the face, passed through his skull, and landed on the ground several feet away. Miraculously, Gage survived, although he lost an eye and had extensive damage to the left frontal lobe of his brain and moderate damage to the right frontal lobe. At first he seemed to recover, but over the next year, his personality changed – instead of the model foreman, he became violent, profane and unable to hold a steady job. Gage's case was the first to suggest a link between personality and the structure of the brain—particularly the frontal lobes.
Furthermore, John Ringo has stated that he conceptually modeled his H7D3 virus after rabies (for the blood-borne phase) which also infects the frontal lobe of the brain and produces anxiety, depression, hallucinations and mania. In yet another parallel with zombie lore, the pharmacological agents used to produce "voodoo" zombies—tetrodotoxin and solanum—have their primary effect to reduce the function of the frontal lobe and are known to produced not just a "mindless" state, but one characterized by "base" emotional reactions and loss of self-control. Thus, whether viral or pharmacological, the characteristic of zombies having no conscious control over violent emotion and physical action is scientifically valid.
While popular fiction and movies often include the concept of a few rare individual zombies able to plan, use tools, and organize their fellows into the pursuit of living prey, this is not really consistent with the "scientific" views presented here. Such traits may require one to accept either the inclusion of a few "voodoo zombies" or that there may be humans with more or less intact cognitive facilities who somehow choose to behave as zombies—perhaps to avoid the attentions of the mob!
So where does that leave us with respect to other "zombie traits" such as slow, shambling movement, animallike vocalization, attacking/biting other people and the supposed craving for brains? The first two are fairly easily explained by brain damage. Ability to make precise, definite movements, to speak, or exercise any conscious activity requires a lot of mental ability. Any damage to the dorsal premotor area or primary sensory and motor cortex will impair the ability to make any movements with a purpose—leaving only the ability to stagger or crawl. Speech requires not just the speech center of the brain termed "Broca's Area," but also the motor cortex areas responsible for mouth, tongue, throat and diaphragm control as well as the language areas of the brain. Impair any of all of these and the best a victim can manage will be grunts, howls and hissing.
Aggressive actions toward other humans will result from suppression of higher cognitive facilities (i.e. frontal lobe suppression). Recent examples in the popular news have reported "drug zombies" who have ingested multiple abused drugs, including "bath salts" (not salts at all, but dangerous chemicals called "cathinones"), and attacked other humans using biting and feeding behaviors. Humans can (and will) eat anything if they require the sustenance—small animals, birds, snakes, rats, etc. With suppression of the "executive functions" of the brain, the victim is left only with the basic needs—chief of which is to feed. Without cognitive facilities to identify what is and is not acceptable food, attacking humans can be expected—especially if that human does not run away as quickly as cats or dogs. Of course craving for brains is largely a product of fiction, but rest assured, if a zombie were to attempt to eat a human, the brains would not be spared!
Zombie Infection: Spreading the Disease
Communicating the zombie condition from one individual to the next is quite frequently central to the zombie story—although not strictly essential. While arguably not "zombie" stories, any "mummy" tale is essentially a Category 1 zombie produced by a mystical curse. In particular, with mystical/magical zombies, the originals must be cursed or subject to mystic forces, even if the subsequent spread is via scratch, bite or simple contact. Most zombie stories, however, treat the "zombie curse" as a simple disease, even if we never learn much about the infectious agent. In the Will Smith movie I Am Legend (from a 1954 book of the same name, written by Richard Matheson) the infectious agent is a virus supposedly developed to cure cancer. In Shaun of the Dead, the agent is an extraterrestrial virus, and in Under a Graveyard Sky, it is a unique "dual-expressing" virus. As is rather typical for John Ringo, he treats us to considerably more background on the origins of the "Infected" in his novels; thus we have a bit more to work with when it comes to real science ideas regarding zombies.
Most readers will have no problem with the concept of an infection spreading from person-to-person via contact. However, the remaining criticisms of the approach amount to one of two issues: (1) how to get the disease to spread rapidly enough to reach epidemic (infecting people faster than it can be treated) or even "pandemic" status (epidemics not limited to a single location), and (2) why should a disease affect behavior? We already addressed issue #2 in the previous section, so we'll concentrate on concentrate on transmission of the disease in this section.
Infectious diseases can affect behavior if either the infectious agent directly affects the cells of the brain, or if the infectious agent produces a toxin. Examples of the former include rabies virus or the bacteria (spirochetes) which cause syphilis and Lyme disease. Likewise, bacterial or mold toxins (such as the ergot alkaloid Lysergic acid—similar to LSD) can alter behavior by substituting for normal chemical "neurotransmitters" of the brain. Bacteria and molds can easily spread through the air, water, food and via contact on surfaces, but they are not very good at spreading from person-to-person. The best means to spread infection rapidly is by virus, and the best way to spread a viral infection to a large number of people at the same time is via airborne viruses such as the ones which cause various forms of flu. Viruses that work best for spreading via direct contact (especially by blood or saliva) are blood-borne. Further, while rabies can affect the brain, the viruses with the greatest affinity for infecting brain tissue are the viruses associated with herpes, smallpox, chicken pox, and shingles. Unfortunately for zombie purposes, those viruses are structurally very different from either rabies or most airborne viruses. Influenza viruses are "RNA viruses" meaning that the infection really consists of a small piece of RNA-based genetic code that enters a host cell and starts making the components of more viruses. Herpeslike viruses are "DNA" viruses in which the genetic code uses the normal cellular machinery in order to replicate, since they "hide" in normally present genes of the cell.
To understand why this is important, consider how DNA and RNA normally operate: Normal cell function is to use DNA as a master copy as if it were a template. DNA consists of two strands, and each strand is a mirror image. When DNA is "copied" into RNA, it can form two new strands—a "positive" copy, and a "negative" copy (from the mirror image strand). The positive RNA contains the actual code for making proteins, while the negative RNA likely has no function. Positive RNA is then used as the template for assembling whatever a living cell requires. When a DNA virus such as Varicella (chicken pox) infects a cell, the viral DNA substitutes for normally present DNA, and fools the cell into making more viruses instead of healthy cell parts. There is some new evidence that the complete code of human genes actually contains inactive pieces that were picked up from some prehistoric viruses! With an RNA virus such as West Nile, the virus contains a single strand of positive RNA that can be immediately used to make more virus copies. However, viruses such as Influenza A (the HxNx flu viruses) have negative RNA that has to be copied into a positive RNA strand before it can start making more virus. Retroviruses such as HIV (AIDS virus) have both strands of RNA, and use them to reverse-engineer the original DNA and insert into the genes of a cell (like those prehistoric viruses above). Negative RNA viruses and retroviruses can only make their copies because the respective viruses also carry along an enzyme called "transcriptase" which makes the positive RNA, or "reverse transcriptase" which makes DNA.
The surprising twist of Under a Graveyard Sky is that some bright, yet currently unknown, villain, has found a way to pack in not just the reverse transcriptase, but another enzyme that causes cells to stop making the airborne RNA viruses, and make bloodborne DNA viruses instead. This is the part where science becomes science fiction since such a method has not yet been discovered in real life, but is not so far beyond current science as to be unimaginable. The theoretical mechanism is fairly simple—influenza viruses such as Ringo's putative H7D1 are negative RNA viruses and still have to include transcriptase enzyme. Once inside a cell, if the positive RNA produced by the transcriptase also codes for reverse transcriptase, the virus may additionally shift from producing more RNA copies, to producing DNA virus copies. With a wave of an author's hand, we now have a bloodborne infection that can spread via bites, punctures, scratches and other forms of close contact. Thus, we have an infection which can spread rapidly and with little notice among a population until it transforms itself into the form which attacks the brain of its victims. Make no mistake, these are two very different viruses, and each can spread independently of the other form. In addition, the new virus form also sets up another key plot point of the story—making the vaccine!
Most protagonists in a zombie story would rightfully argue that the only way to truly cure a zombie… is to kill the host, thereby also destroying the disease. Yet no matter whether we hypothesize a mystical or disease source for the zombie "curse" (and provided the victims are actually alive, and not walking dead), there should be some means to "cure" those zombies. If the zombie condition is indeed a magical curse, finding and eliminating the source of that curse should be sufficient to restore the zombie to humanity. Surprisingly, the scientific approach to a zombie "disease" starts much the same way, although it will require additional steps to apply and spread that cure.
The previous section postulated a viral source for our zombie infection. Human science has become very proficient at identifying both bacterial and viral sources of infection. It may take a bit longer to trace the origin, but as long as medical facilities survive long enough to examine the Infected, it should be possible to prevent the disease via vaccine, even if it cannot be cured outright. If the infection is one that causes simply suppression of higher cognitive functions (as would be caused by a toxin of pharmacological agent) then removing the source of that suppression should allow the victim to return to normal. However, if any permanent damage to the brain cells or connections has occurred—even with identification of the infection source, it may not be possible to restore normal brain or body function.
The best way to cure or prevent any disease is to let the human immune system take care of the job for you. When bacteria, viruses or alien organisms invade the human body, it forms antibodies which assist in destroying the foreign tissue. Often, however, it can be a race between creating enough antibodies to cure the infection before the foreign material replicates enough to seriously sicken the host. Thus, a mechanism is required to produce antibodies prior to infection—in other words, a vaccine. Antibodies do not have to form in response to the exact infectious agent, as discovered by Edward Jenner in 1796 when he discovered that milkmaids contracting cowpox appeared immune to the much more deadly smallpox. A human patient injected with a much milder form of either the same or a similar disease have the opportunity to develop antibodies with either no symptoms or much less severe symptoms. For the greatest effectiveness, the actual viral/bacteriological agent must be used, but in an inactivated or attenuated form. When there is the luxury of enough time to create the vaccine, scientists use the fact that viruses mutated, and breed the virus in culture for many generations, hoping for a less severe version for their vaccine—this is what Will Smith's character is doing in I Am Legend.
When time is critical, however, the potent virus can be "inactivated" or killed by chemical or radiological means, and still be used for vaccine production. In Under a Graveyard Sky, the Smith family gets ensnared in a scheme to (illegally) produce vaccine using virus harvested from live Infected. The question of exactly what tissues to use for harvesting virus could easily have been handwaved away by the author, but Ringo chose to use rabies as a model, and have the blood-borne "zombie-making" virus concentrate in the spinal cord. While brain tissue (particularly frontal lobes of the brain) would also make sense based on the site of action of the virus, Ringo's choice is consistent not only with rabies, but also with the aforementioned Varicella and herpes viruses which concentrate in spinal cord and in the ganglia lining the spinal cord. It is certainly likely that any virus seriously affecting the brain can be found much more readily in the spinal cord than in other parts of the body, and with good fictional plotting, that point alone sets up more of the drama and conflict of the story!
There is always a question of whether a vaccine will provide any protection from a disease once the infection takes hold in a victim. For greatest protection, the immune system needs to start producing antibodies before the infection can reproduce. If a person is already fully infected, a vaccine may at best cause a milder form of the disease. Then again, there is always a statistical chance that a person develops sufficient antibodies (or contracts a mild/mutated disease) to be immune already. Survivors in close contact with infected may have their own antibody—or they may just have never gotten the most potent form of the disease. From a medical perspective, it would certainly be interesting to test the survivors for antibodies in Under a Graveyard Sky—from a purely fictional perspective—to see if their blood could have been used to produce the needed antibody.
No description of "curing" a zombie plague would be complete without at least a passing discussion of defeating and killing zombies in combat. The best answer I can give to "how" is—from as far away as possible. John Ringo, Michael Z. Williamson, Larry Correia, Sarah A. Hoyt and I have all participated in a fun convention panel entitled "Messiest Ways to Kill Zombies" in which our first assumption is that no contamination occurs from contact with blood and tissue. However, isolating from contact—what medical professionals call "universal precautions" should be the first "realistic" preparation for combat. Zombie Hunters should be very careful not to become victims themselves.
The next step involves knowing exactly which "injuries" will stop a particular type of zombie. It has always amused me that the traditional attack on "undead" creatures, is always to go for portions of the body which are supposedly lacking or nonfunctional—the brain in zombies, the heart in vampires. Given a mystical zombie curse, the only defense is typically to render the zombie into small enough pieces that it is no longer a threat. For reanimated corpses, it makes as much sense to target the brain as any other body part, since the reanimation force likely substitutes for brain activity—separate that from the rest of the body and again, it becomes no threat to the hunter. For "living" zombies and Infected, brain and heart become the major targets, since the lack of higher thought processes means that pain or any lesser injury would not interrupt the zombie attack. Once the brain or heart are severely disrupted, the zombie should finally cease the attack, unless one is very, very unlucky (or in a Larry Correia novel). In the process, though, a good hunter remembers to use a caliber sufficient to incapacitate the Infected—a lesson largely lost on Max Brooks when he incorrectly assumed in World War Z that a mere .22 caliber round would penetrate the head from more than a few feet away. Hunters! Be like Faith Smith and insist on large caliber ammo!
Final Thoughts on Scientific vs. Fictional Zombies
A friend of mine likes to jokingly respond on panels at science fiction conventions: "No, we're talking about real zombies." In this article, we've treated zombies as a real, scientifically based phenomenon. There are many historical (and hysterical) reports of zombielike behavior that can be attributed to natural causes, and those causes are extrapolated here to speculate a scientific basis for a zombie plague. By extension, we also speculate on how to deal with such a plague using a similar scientific rationale. There are many questions we have not addressed: such as how zombies coordinate swarms, why they howl, why they don't attack each other… but many of those questions really result from how an author/screenwriter chooses to write their zombie universe. Until we are truly faced with a zombie apocalypse, we can only speculate …
… and prepare.
Copyright © 2013 by Dr. Tedd Roberts
Dr. Tedd Roberts, known to many science fiction fans as "Speaker to Lab Animals," is a research scientist in neuroscience. For the past thirty years, his research has concentrated on how the brain encodes information about the outside world, how that information is represented by electrical and chemical activity of brain cells, and the transformation of that information into movement and behavior. He blogs about his work here.