D. Taste
Little is known about the altered taste buds of the walking dead. Zombies do have the ability to tell human flesh apart from that of animals, and they prefer the former. Ghouls also have a remarkable ability to reject carrion in favor of freshly killed meat. A human body that has been dead longer than twelve to eighteen hours will be rejected as food. The same goes for cadavers that have been embalmed or otherwise preserved. Whether this has anything to do with “taste” is not yet certain. It may have to do with smell or, perhaps, another instinct that has not been discovered. As to exactly why human flesh is preferable, science has yet to find an answer to this confounding, frustrating, terrifying question.
E. Touch
Zombies have, literally, no physical sensations. All nerve receptors throughout the body remain dead after reanimation. This is truly their greatest and most terrifying advantage over the living. We, as humans, have the ability to experience physical pain as a signal of bodily damage. Our brain classifies such sensations, matches them to the experience that instigated them, and then files the information away for use as a warning against future harm. It is this gift of physiology and instinct that has allowed us to survive as a species. It is why we value virtues such as courage, which inspires people to perform actions despite warnings of danger. The inability to recognize and avoid pain is what makes the walking dead so formidable. Wounds will not be noticed and, therefore, will not deter an attack. Even if a zombie’s body is severely damaged, it will continue to attack until nothing remains.
F. Sixth Sense
Historical research, coupled with laboratory and field observation, have shown that the walking dead have been known to attack even when all their sensory organs have been damaged or completely decomposed. Does this mean that zombies possess a sixth sense? Perhaps. Living humans use less than 5 percent of their brain capacity. It is possible that the virus can stimulate another sensory ability that has been forgotten by evolution. This theory is one of the most hotly debated in the war against the undead. So far, no scientific evidence has been found to support either side.
G. Healing
Despite legends and ancient folklore, undead physiology has been proven to possess no powers of regeneration. Cells that are damaged stay damaged. Any wounds, no matter what their size and nature, will remain for the duration of that body’s reanimation. A variety of medical treatments have been attempted to stimulate the healing process in captured ghouls. None were successful. This inability to self-repair, something that we as living beings take for granted, is a severe disadvantage to the undead. For example, every time we physically exert ourselves, we tear our muscles. With time, these muscles rebuild to a stronger state than before. A ghoul’s muscle mass will remain damaged, reducing its effectiveness every time it is used.
H. Decomposition
The average zombie “life span”—how long it is able to function before completely rotting away—is estimated at three to five years. As fantastic as this sounds—a human corpse able to ward off the natural effects of decay—its cause is rooted in basic biology. When a human body dies, its flesh is immediately set upon by billions of microscopic organisms. These organisms were always present, in the external environment and within the body itself. In life, the immune system stood as a barrier between these organisms and their target. In death, that barrier is removed. The organisms begin multiplying exponentially as they proceed to eat and, thereby, break down the corpse on a cellular level. The smell and discoloration associated with any decaying meat are the biological process of these microbes at work. When you order an “aged” steak, you are ordering a piece of meat that has begun to rot, its formerly toughened flesh softened by microorganisms breaking down its sturdy fiber. Within a short time, that steak, like a human corpse, will dissolve to nothing, leaving behind only material too hard or innutritious for any microbe, such as bone, teeth, nails, and hair. This is the normal cycle of life, nature’s way of recycling nutrients back into the food chain. To halt this process, and preserve dead tissue, it is necessary to place it in an environment unsuitable for bacteria, such as in extreme low or high temperatures, in toxic chemicals such as formaldehyde, or, in this case, to saturate it with Solanum.
Almost all the microbe species involved in normal human decomposition have repeatedly rejected flesh infected by the virus, effectively embalming the zombie. Were this not the case, combating the living dead would be as easy as avoiding them for several weeks or even days until they rotted away to bones. Research has yet to discover the exact cause of this condition. It has been determined that at least some microbe species ignore the repelling effects of Solanum—otherwise, the undead would remain perfectly preserved forever. It has also been determined that natural conditions such as moisture and temperature play an important role as well. Undead that prowl the bayous of Louisiana are unlikely to last as long as those in the cold, dry Gobi desert. Extreme situations, such as deep freezing or immersion in preservative fluid, could, hypothetically, allow an undead specimen to exist indefinitely. These techniques have been known to allow zombies to function for decades, if not centuries. (See “Recorded Attacks.”) Decomposition does not mean that a member of the walking dead will simply drop. Decay may affect various parts of the body at different times. Specimens have been found with brains intact but nearly disintegrated bodies. Others with partially rotted brains may control some bodily functions but be completely paralyzed in others. A popular theory has recently circulated that attempts to explain the story of the ancient Egyptian mummy as one of the first examples of an embalmed zombie. The preservation techniques allowed it to function several thousand years after being entombed. Anyone with a rudimentary knowledge of ancient Egypt would find this story almost laughably untrue: The most important and complicated step in preparing a pharaoh for burial was the removal of the brain!
I. Digestion
Recent evidence has once and for all discounted the theory that human flesh is the fuel for the undead. A zombie’s digestive tract is completely dormant. The complex system that processes food, extracts nutrition, and excretes waste does not factor into a zombie’s physiology. Autopsies conducted on neutralized undead have shown that their “food” lies in its original, undigested state at all sections of the tract. This partially chewed, slowly rotting matter will continue to accumulate, as the zombie devours more victims, until it is forced through the anus, or literally bursts through the stomach or intestinal lining. While this more dramatic example of non-digestion is rare, hundreds of eyewitness reports have confirmed undead to have distended bellies. One captured and dissected specimen was found to contain 211 pounds of flesh within its system! Even rarer accounts have confirmed that zombies continue to feed long after their digestive tracts have exploded from within.