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When someone dies, it may be the end of their journey through this world, but this is not the case with their body. Instead, it will begin the long process of shedding its components. So, what happens when bodies decompose, and why should we learn about it?

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Decomposition is what naturally occurs to bodies after death. What is there to know about it?

For the majority of us, contact with the bodies of people who have passed away begins and ends with the sad occasion of a funeral.

And even then, what we usually get is either an urn with the person’s cremated remains, or a body laid out neatly in a casket, having been carefully prepared for the occasion by a funeral home.

What happens to bodies naturally, after they have had their grand encounter with death? What if they don’t get cremated or choose to become embalmed, so as to delay the process of decomposition and keep them “fit” for viewing for longer?

Under natural conditions — for example, if the body is left out in a natural environment, or placed in a shallow grave — a lifeless body begins to slowly disintegrate, until only the bones are left for future archeologists to dig up.

In this Spotlight, we describe the process of decomposition and explain why it can be useful to understand what happens to the body after death.

Although many of us may think of decomposition as synonymous with putrefaction, it is not. In fact, the decomposition of a human body is a longer process with many stages, of which putrefaction is only one part.

Decomposition is a phenomenon through which the complex organic components of a previously living organism gradually separate into ever simpler elements.

In the words of forensic scientist M. Lee Goff, it is “a continuous process, beginning at the point of death and ending when the body has been reduced to a skeleton.”

There are several signs that a body has begun its process of decomposition, Goff explains. Perhaps the three best-known ones, which are often cited in crime dramas, are livor mortis, rigor mortis, and algor mortis.

Livor, rigor, and algor mortis

Livor mortis, or lividity, refers to the point at which a deceased person’s body becomes very pale, or ashen, soon after death. This is due to the loss of blood circulation as the heart stops beating.

Goff explains, “[T]he blood begins to settle, by gravity, to the lowest portions of the body,” causing the skin to become discolored. This process may begin after about an hour following death and can continue to develop until the 9–12 hour mark postmortem.

In rigor mortis, the body becomes stiff and completely unpliable, as all the muscles tense due to changes that occur in them at a cellular level. Rigor mortis settles in at 2–6 hours after death and can last for 24–84 hours. After this, the muscles become limp and pliable once more.

Another early process is that of algor mortis, which occurs when the body goes cold as it “ceases to regulate its internal temperature.” How cold a body will go largely depends on its ambient temperature, which it naturally matches within a period of about 18–20 hours after death.

Other signs of decomposition include the body assuming a greenish tinge, skin coming off the body, marbling, tache noire, and, of course, putrefaction.

Other signs of decomposition

The greenish tint that the body may assume after death is due to the fact that gases accumulate within its cavities, a significant component of which is a substance known as hydrogen sulfide.

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Putrefaction is ‘nature’s recycling process.’

This, Goff writes, reacts “with the hemoglobin in blood to form sulfhemoglobin,” or the greenish pigment that gives dead bodies their uncanny color.

As for skin slippage — in which the skin neatly separates from the body — it might sound less disturbing once we remember that the whole outer, protective layer of our skin is, in fact, made out of dead cells.

“The outer layer of skin, stratum corneum, is dead. It is supposed to be dead and fills a vital role in water conservation and protection of the underlying (live) skin,” Goff explains.

This layer is constantly being shed and replaced by underlying epidermis. Upon death, in moist or wet habitats, epidermis begins to separate from the underlying dermis […] [and it] can then easily be removed from the body.”

M. Lee Goff

When the skin comes clean off of a dead person’s hands, it is typically known as “glove formation.”

A phenomenon known as “marbling” occurs when certain types of bacteria found in the abdomen “migrate” to the blood vessels, causing them to assume a purple-greenish tint. This effect gives the skin on some body parts — usually the trunk, legs, and arms — the appearance of marble (hence its name).

Moreover, in instances wherein the eyes remain open after death, “the exposed part of the cornea will dry, leaving a red-orange to black discoloration,” Goff explains. This is referred to as “tache noire,” which means “black stain” in French.

Finally, there is putrefaction, which Goff calls “nature’s recycling process.” It is facilitated by the concerted actions of bacterial, fungal, insect, and scavenger agents over time, until the body is stripped of all soft tissue and only the skeleton remains.

Goff also notes that different scientists split the process of decomposition into different numbers of stages, but he advises considering five distinct stages.

The first one, the fresh stage, refers to the body right after death, when few signs of decomposition are visible. Some processes that may begin at this point include greenish discoloration, livor mortis, and tache noire.

Some insects — typically flies — may also arrive at this stage, to lay the eggs from which larvae will later hatch, which will contribute to stripping the skeleton of the surrounding soft tissue.

“As revolting as they may seem, flies and their larvae — maggots — are created perfectly for the job they need to do and many experts call them ‘the unseen undertakers of the world,'” writes pathology technician Carla Valentine in her book.

The egg-laying flies that are attracted to dead bodies, she explains, “are mainly bluebottles from the Calliphora genus,” which will “lay eggs on orifices or wounds only, because the very young larvae need to eat decaying flesh but can’t break the skin to feed.”

Another type of fly, she adds, “doesn’t lay eggs but tiny maggots, which can start consuming flesh immediately. These are descriptively named Sarcophagidae or ‘flesh flies.'”

At the second stage of decomposition, the bloated stage, is when putrefaction begins. Gases that accumulate in the abdomen, therefore causing it to swell, give the body a bloated appearance.

Down to the bones

During the third stage, that of decay, the skin breaks due to putrefaction and the action of maggots, allowing the accumulated gases to escape. Partly for this reason, this is when the body emanates strong, distinctive odors.

Mortician Caitlin Doughty offers a striking description of these smells in her book Smoke Gets In Your Eyes:

[T]he first note of a putrefying human body is of licorice with a strong citrus undertone. Not a fresh, summer citrus, mind you — more like a can of orange-scented industrial bathroom spray shot directly up your nose. Add to that a day-old glass of white wine that has begun to attract flies. Top it off with a bucket of fish left in the sun. That […] is what human decomposition smells like.”

Postdecay is the next-to-last stage of decomposition, in which, as Goff writes, “the body is reduced to skin, cartilage, and bone.” At this point, various types of beetle usually come in to remove the softer tissue, leaving only the bones behind.

The final stage of decomposition is the skeletal stage, in which only the skeleton — and sometimes hair — is left.

How long it takes for a body to decompose largely depends on the geographical area in which the body is found and the interaction of environmental conditions. If a body is found in a dry climate, with either very low or very high temperatures, it could mummify.

At this point, you may well be wondering, “How could learning all these details about a body’s process of decomposition after death be of any use to me?”

Well, Doughty explains that in today’s world, thinking about death and discussing any aspects related to it have become taboo.

We can do our best to push death to the margins, keeping corpses behind stainless-steel doors and tucking the sick and dying in hospital rooms. So masterfully do we hide death, you would almost believe we are the first generation of immortals. But we are not.”

Caitlin Doughty

This implicit ban on death-related topics, she says, can only deepen people’s fear of death — both their own and that of others — and contribute to spreading misinformation about dead bodies as places of contamination.

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The myth that dead bodies are spaces of contagion persists despite the overwhelming evidence indicating otherwise.

Which is why, she writes, “[a] reminder of our fallibility is beneficial, and there is much to be gained by bringing back responsible exposure to decomposition.”

Having a clear idea of what happens to a body after death should help to remove the aura of dread surrounding the awareness of our own mortality. And, it can also help us to care for loved ones better, even beyond their final moments.

Scientists have noted that, for instance, the mistaken idea that dead bodies can easily spread disease is “a myth too tough to die,” often supported by the sensationalistic depiction of cadavers in the media.

This problem is particularly bad in the case of fatalities that are caused by natural disasters. Yet, as the dedicated World Health Organization (WHO) page clearly states, “dead bodies from natural disasters generally do not cause epidemics.”

“For over 20 years we have known that the bodies of those killed in natural disasters do not cause outbreaks of infectious diseases,” write the authors of a special report published in the Pan American Journal of Public Health.

Understanding that dead bodies do not automatically pose a threat to health, they argue, can lead to better policies surrounding death, and it can help those left behind to come to terms with their loss in a natural, progressive timeline.

We hope that the information provided in this Spotlight will help you to navigate your relationship with mortality and your own body as part of the natural world.