Rock the Rot: Demystifying Decay in the Undead
With a fondness that the uninitiated have difficulty fathoming, we fans of the undead often find ourselves referring to the zombie scourge as rotters. But the use of such an epithet belies a systemic lapse by contributors to the literature: our rotters don’t rot. At least, not in ways that adhere to the natural processes of decay.
Putting aside arguments of suspension of disbelief (after all, we’re talking reanimation here!), it’s understandable that writers in the genre generally eschew the technical minutiae of decay in their stories, opting instead to focus on the dramatic details that move a plot along. What fun would it be if we forced our zombies to conform strictly to the laws governing decomposition? A walker that stiffens up with rigor after a few hours, or simply falls apart within a few days because its tissues have turned to goo, is no longer going to be able to chase you. That doesn’t make for a very frightening scenario. Or an entertaining one for that matter, depending of course on your point of view.
But the judicious insertion of a few choice gory (and technically correct) morsels can add a lot to an otherwise shambling tale. Factual details can lend a sense of realism. They can enhance the reader’s guttural sensitivity to scenes, greatly heightening terror and disgust. Most importantly, a little inventive description can help excuse zombies from the rules of rot, even if the rest of us are destined to become dust.
Taphonomists (people who study the decomposition of organisms) and forensic pathologists describe five general stages in human decomposition:
- Initial Decay (also amusingly referred to as “Fresh”)
- Advanced Decay
- Dry (or Remains)
Initial Decay (0-2 days post mortem)
- Autolysis – “Self-eating.” Aerobic (oxygen-dependent) respiration and energy production cease, resulting in a loss of cellular homeostasis and integrity. Carbon dioxide accumulates, raising tissue pH and triggering the release of catabolic (digestive) enzymes from cellular storage structures (lysosomes). The cells are literally digested from the inside out. Destruction of the membrane releases cytoplasmic constituents into the spaces between cells, essentially turning tissues into vichyssoise.
- Algor mortis – Body temperature begins to drop almost immediately following death.
- Livor mortis – Also called lividity. Blood pools under force of gravity to lower portions of the body.
- Rigor mortis – Occurring 2-6 hours post mortem, the stiffness (rigor) is caused by the leakage of calcium ions into muscle tissues, thus preventing the relaxation of contractile proteins. The state peaks roughly 12 hours post mortem and dissipates until putrefaction begins (roughly 2-3 days after death).
- Putrefaction – No longer held in check by the body’s natural defense mechanisms, bacteria (mostly from the stomach and intestines) begin to proliferate. They spread to all parts of the body primarily via the lymphatic and vascular systems. Fungi also begin to flourish.
Bloat (2 days post mortem)
- Bloating – Anaerobic bacteria (not requiring oxygen) produce various gaseous byproducts (hydrogen sulfide, carbon dioxide, methane, nitrogen). A body in “full bloat” can be swollen to twice its original size. Abdominal distension usually occurs first, as this is the site of initial putrefaction.
- Frothing – Tissue liquefaction and the buildup of pressure can force the escape of fluids from various orifices (mouth, eyes, nose, anus).
- Marbling – Compounds produced during putrefaction interact with blood components and discolor the skin (green, blue, red, black, yellow), yielding vividly colored, grossly distended corpses.
- Blistering – Accumulation of gasses and fluids, as well as pockets of bacterial growth, can cause bubbles to form under the skin.
- Infestation – Bloating triggers the arrival of flies (typically blow flies and flesh flies), which lay their eggs in any available opening, especially the orifices of the face, but also in wounds, if present. Maggots hatch a day later, producing a thick crawling swarm. The face is often consumed the fastest, as it is where most of the eggs are laid. Subdermal masses of larvae can cause skin slippage and detachment of hair, as well as skin rupturing.
Purge (3 days post mortem)
- Leakage – The nitrogen-rich soup of liquefied tissue and waste leaks from the body through all orifices and ruptures.
- Shrinkage – The release reverses the bloating, leading to a rapid loss in mass. The process is aided by maggots migrating away to pupate.
Advanced Decay (2-3 weeks post mortem)
- Mummification – Sunlight and heat eliminate liquid, causing desiccation, which slows microbial decay. Due to the steady reduction in mass due to leakage and other factors, putrefaction slows. At lower temperatures and in the shade, decay can continue for extended periods of time, allowing environmental bacteria and fungi to invade the body. Many of these are brought by flies and beetles. Some bacteria release chemicals that attract certain types of insects whose saliva contains chemicals that kill off competing bacteria.
Dry/Remains (6 months to a year post mortem)
- Skeletonization – One of the last stages of decay, skeletonization is characterized by the complete loss of all soft tissues, leaving only skin, hair or fur, bones and teeth, and cartilage. The process can be accelerated where scavenging occurs. In some cases, carrion eaters can remove soft tissues within hours or days, bypassing certain steps in the decay process.
The Decomp-Defying Corpse
As might be gleaned from the above, the two most important factors determining the rate of decay are heat and humidity, as they will impact all other processes, whether chemical, microbial, or physical. But in order to delay, or even to arrest, decomposition, the body must be made resistant to the agents which mediate biochemical and physical breakdown. The writer who addresses this in some way pays an immense compliment to the intelligence of the reader.
There are three factors which can be useful to consider when designing a rotter that resists rotting:
- Freezing (cryonics)
- Desiccation (mummification)
- Chemical preservation (embalming, plastination).
All slow the biological and chemical processes and render the tissues inhospitable to microbes.
In my cyberpunk series, GAMELAND, for example, I chose to make my zombies resistant to decay through tissue plastination. You may be familiar with the process as it is used by the traveling exhibition show Body Worlds in their display of preserved human bodies. Invented by Gunther von Hagens in 1977, plastination replaces water and lipid tissues with synthetic polymers. What distinguishes plastination in my series is that it is naturally mediated by biological events resulting from infection. Plastination explains both how my rotters can remain intact a decade after death, as well as retain full mobility. It’s also why my zombies are described as smelling like burnt plastic, with the added benefit that the “synthetic” stench discourages scavengers from feeding on them.
So, now that you know more about decomposition than you ever wished you did, you can immerse yourself in your next rotter book with a little more assurance that your favorite monster will stick around to terrify you for years to come.
Some additional decomp-related terms I find interesting:
- Necrobiom – the unique and often remarkably complex ecosystem which forms as a result of the presence of a corpse (dead person) or carcass (dead animal), including insects, the mice which prey on them, and the predators which in turn feed on the mice (snakes and other larger animals).
- Grave wax or adipocere – The formation of a crumbly white, waxy substance around fatty parts of the body, such as the cheeks, breasts, abdomen, and buttocks, caused by the reaction of fats with water and hydrogen in the presence of bacterial enzymes (saponification, which is the process by which soap is formed). The substance is resistant to bacteria and can help protect a corpse, further slowing decomposition. The appearance of grave wax begins within a month of death and can persist for years and decades.
Finally, if you’d like to check out a short video about the Freeman Ranch body farm where the processes of decomposition are studied, click through here. It’s wonderfully gory.
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