The amount of time it takes for a body to completely decompose depends on many factors. The decomposition process begins immediately after death, and the overall timeline can vary dramatically based on the environment and other variables. Here is a detailed look at the decomposition process and how long a dead body typically lasts under different conditions.
What Happens to a Body After Death?
Immediately after death, the body enters a stage called algor mortis, during which the body cools to ambient temperature. The cooling begins immediately, proceeding at a rate of about 1.5°F per hour. After around 12 hours, the body will be as cool as its surroundings.
At the same time, rigor mortis sets in. This causes the muscles to stiffen due to chemical changes in the muscles. The process begins within 2-6 hours of death, spreading from the face and neck downward through the body. Rigor mortis peaks at around 12 hours, and dissipates roughly 72 hours after death.
Decomposition begins almost immediately after death. Within minutes, processes within the body’s cells begin to break down and cause them to release enzymes that initiate decomposition. Within 24 hours, visible signs of decomposition become noticeable.
The body then begins to bloat due to gases building up inside. The green discoloration of decomposition also becomes visible, usually in the right lower abdomen. This is known as “marbling”. Over the next several days, the body’s bloating will increase. The gases within the body also begin to escape through the mouth, nostrils, and other orifices.
Over the course of the next few weeks to months, the body’s tissues will break down further and liquify. The skin may blister and eventually rupture, allowing the underlying decay to become visible. This liquefaction allows organs, muscles, and tissues to eventually seep out if the body is on a porous surface. The strong smell of ammonia will also be present as nitrogen is released during decomposition.
Over a prolonged period, the body’s structures will continue deteriorating to skeletal remains. How long this takes depends strongly on the environment and conditions the body is in. Heavier, well-insulated body parts like the torso take the longest to decompose. Lightly covered and less insulated areas like the head and limbs skeletonize first.
What Factors Affect the Rate of Decay?
There are many different variables that affect how fast a body decomposes. Key factors include:
- Temperature – Heat accelerates bacterial growth and chemical reactions. Bodies decompose fastest in hot conditions.
- Access to oxygen – Bodies decay faster in open air versus completely buried.
- Insect and animal scavenging – Scavengers can remove flesh and accelerate skeletonization.
- Rain and moisture – Bodies decompose faster in moist conditions that promote bacteria growth.
- Body size and fat content – Obese bodies decompose slower than thin bodies.
- Clothing and coverings – Barriers slow down insect and animal scavenging.
- Depth underground – Bodies buried deeper decompose slower.
- Embalming – Chemical embalming preserves bodies longer.
Generally, bodies left completely exposed in hot, humid climates will decompose the fastest, while embalmed bodies properly buried in coffins and vaults will take the longest. Bodies submerged in water often decompose significantly slower than on land.
Stages of Decay
While the broad timeline varies, the process of decomposition generally occurs in four main stages:
Fresh Stage
The fresh stage begins immediately after death. At this point, insect activity and scavenging may begin, although bloating and strong odor have not yet set in. The body cools to ambient temperature. Rigor mortis peaks and begins to fade. Overall decay during the fresh stage usually remains minimal. The fresh stage typically lasts 1-2 days, but can persist longer in cooler conditions.
Bloat Stage
The bloat stage usually sets in 1-3 days after death. As gases build up inside, the abdomen swells. Skin discoloration and marbling becomes visible. The release of gases creates notable odors. Maggots may be visible in orifices. Bloating spreads the legs, arms, and tongue. This stage typically lasts around 3-4 days in warm weather.
Active Decay Stage
The active decay stage follows after bloating subsides. Tissues and structures liquefy, and may seep out if the body rests on a porous surface. The strong odors intensify as gases escape and bacteria rapidly multiply. Maggots and insects become abundant. Liquids may pool under the body at this stage. Active decay lasts around 10-25 days.
Skeletonization Stage
During skeletonization, the last remnants of skin, tissue, and organs deteriorate leaving just the bones behind. Bleaching may occur due to sun exposure. Once skeletonization is complete, the bones begin to dry out and eventually disintegrate to dust under further weathering processes. The skeletonization stage can take weeks to years depending on conditions.
Average Timelines in Different Circumstances
While the progression through the decay stages is relatively consistent, how long the overall decomposition process takes can vary dramatically based on conditions. Here are some estimates for how long a body will last under different circumstances:
On the body’s surface outdoors:
- Summer (hot/humid) – up to 4 weeks for skeletonization
- Winter (freezing) – 4-6 months for skeletonization
- Desert (hot/dry) – up to 1-2 years for skeletonization
– Bodies left on the ground surface and exposed to insects, animals and weather decompose the fastest. Heat accelerates the process while cold temperatures can significantly delay it.
Buried in shallow grave:
- 2-4 weeks in summer
- 8-10 weeks in winter
– Shallow graves still allow insect and animal activity which speeds decay. Cold ground temperatures slow the process.
Inside a structure:
- 6-12 months for skeletonization
– Structures provide protection and moderate temperatures, resulting in a slower timeline.
Buried deep underground:
- 5-10 years for skeletonization
– Deep burial eliminates most insect/animal activity and provides more stable, cooler temperatures.
Submerged in water:
- 2 weeks in summer
- 8 weeks in winter
- 2+ years if completely submerged
– Water retards decay by cooling the body and preventing insect activity. Completely submerged bodies decay extremely slowly.
Cremated:
- Instant destruction of organic matter
- Powdered remains persist almost indefinitely
– Cremation rapidly destroys the body at high temperatures, leaving just skeletal remains behind.
Embalmed:
- Preserves the body longer than unembalmed remains
- May extend the overall timeline by 1-2x
– Chemical embalming preserves the tissues and slows decomposition. Bodies embalmed and entombed may last many decades.
Special Cases
Mummification
Natural or artificial mummification can essentially halt the decay process and preserve bodies for centuries or millennia. Mummies have persisted for over 5,000 years in some instances. The most famous examples are Egyptian mummies, created through extensive artificial preservation steps.
However, mummification can also happen naturally. Bodies have been found freeze-dried, soaked in tar, or desiccated in dry caves. The extreme conditions prevent bacteria growth and decay.
Adipocere Formation
Also called “grave wax”, adipocere is a grayish, waxy substance that can form on bodies in very wet conditions. The saturated fat tissues react with the moisture and hydrogenate into the waxy material. Adipocere formation can significantly retard decay for decades and preserve body shapes. It occurs more readily in obese bodies.
Autoclaving
Autoclaving is an accelerated decomposition process using high-pressure steam. It kills microbes and breaks down tissues more quickly than natural decay. Liquefaction and skeletonization can occur in around 2-3 hours. While not a natural process, autoclaving is occasionally used to speed up studies of human decomposition.
Methane Digester
As an emerging green disposal method, commercial methane digesters are occasionally used on farm animal carcasses. The body is submerged in a vat and bacteria breaks down the remains into methane gas fuel. For a human body, skeletonization typically occurs within 30-45 days as the tissues rapidly liquefy. The accelerated breakdown produces a high volume of methane.
Other Factors That Affect Decomposition
Beyond the primary factors like temperature, moisture and accessibility to insects/scavengers, other variables can have an influence on the decay rate:
– Clothing and wrappings – Clothing can interfere with insect activity and slow external decay.
– Trauma – Severe trauma or dismemberment exposes more surface area and accelerates decay.
– Location – Bodies decompose faster outdoors versus indoors where temperatures are more regulated.
– Coffin/casket materials – Metal coffins slow decay while wood coffins allow easier access to insects.
– Burial practices – Vaults, sealed coffins, and deeper burial all extend the decay timeline.
– Ground pH – Acidic soils accelerate breakdown of tissues. Alkaline soils slow the process.
– Body fat – Obese bodies decay slower than lean bodies.
Stages of Skeletonization
The skeletonization stage itself has a wide timeframe. It begins once skeletonization starts and ends when the bones have disintegrated. Major events include:
Early Skeletonization
The early skeletonization phase starts when all soft tissues have liquefied or been scavenged away. Much of the skeleton is still partially greasy, and dripping decomposition fluids. Bones have a dark coloration.
Bleaching
After initial skeletonization, sun exposure will gradually bleach and dry the bones. Bleaching typically starts on bones exposed upright towards the sun. The pale white bleach lines gradually spread over months or years.
Disarticulation
As ligaments deteriorate, smaller bones eventually separate from the body – ribs, vertebrae, phalanges, etc. This occurs over months and years after initial skeletonization.
Weathering and Disintegration
Given enough time, weathering will gradually cause the bones to weaken and disintegrate into fragments. This process takes decades or centuries depending on the conditions. Bones protected from the elements last the longest.
| Skeletonization Stage | Time Period |
|---|---|
| Early Skeletonization | 0 – 6 months |
| Bleaching | 1 – 5 years |
| Disarticulation | 1 – 10 years |
| Weathering and Disintegration | 10+ years |
The total time for complete skeleton breakdown to occur often ranges from 10 to 50 years. Heavy bones like the femur and skull withstand weathering the longest. Teeth can persist for decades after all other bones have disappeared. Factors like moisture, temperature swings, and acidity affect the pace of disintegration.
Conclusion
In conclusion, the decomposition timeline for a body can range dramatically from a few weeks to many years depending on the conditions and environment it is exposed to. Heat, moisture, and accessibility by insects and scavengers accelerate the process, while colder and more protected conditions extend the timeline. Natural mummification can essentially halt decay, while practices like embalming can significantly delay the process. Overall, the normal timeline for complete skeletonization of an exposed body is usually 6 months to 4 years.