For other uses, see Decomposition (disambiguation).
Stages of death

1. Pallor mortis
2. Algor mortis
3. Rigor mortis
4. Livor mortis
5. Putrefaction
6. Decomposition
7. Skeletonization

Decomposition is the process by which organic substances are broken down into much simpler matter. The process is essential for recycling the finite matter that occupies physical space in the biome. Bodies of living organisms begin to decompose shortly after death. Animals, such as worms, also help decompose the organic materials. Organisms that do this are known as decomposers. Although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is generally referred to as taphonomy from the Greek word τάφος taphos, meaning tomb.

One can differentiate abiotic from biotic decomposition (biodegradation). The former means "degradation of a substance by chemical or physical processes, e.g., hydrolysis.[1] The latter means "the metabolic breakdown of materials into simpler components by living organisms",[2] typically by microorganisms.

Animal decomposition

Ants eating a dead snake



Stages of decomposition

Five general stages are used to describe the process of decomposition in vertebrate animals: fresh, bloat, active and advanced decay, and dry/remains.[6] The general stages of decomposition are coupled with two stages of chemical decomposition: autolysis and putrefaction.[7] These two stages contribute to the chemical process of decomposition, which breaks down the main components of the body.


The fresh stage begins immediately after the heart stops beating. A person can be revived, especially if someone with Cardiopulmonary resuscitation skills is nearby.[8] From the moment of death, the body begins cooling or warming to match the temperature of the ambient environment, during a stage called algor mortis.[9] Shortly after death, within three to six hours, the muscular tissues become rigid and incapable of relaxing, during a stage called rigor mortis. Since blood is no longer being pumped through the body, gravity causes it to drain to the dependent portions of the body, creating an overall bluish-purple discolouration termed livor mortis or, more commonly, lividity.




Blowflies and flesh flies are the first carrion insects to arrive, and they seek a suitable oviposition site.[6]


The bloat stage provides the first clear visual sign that microbial proliferation is underway. In this stage, anaerobic metabolism takes place, leading to the accumulation of gases, such as hydrogen sulfide, carbon dioxide, methane, and nitrogen. The accumulation of gases within the bodily cavity causes the distention of the abdomen and gives a cadaver its overall bloated appearance.[11] The gases produced also cause natural liquids and liquefying tissues to become frothy.[9] As the pressure of the gases within the body increases, fluids are forced to escape from natural orifices, such as the nose, mouth, and anus, and enter the surrounding environment. The buildup of pressure combined with the loss of integrity of the skin may also cause the body to rupture.[11]


If insects have access, maggots hatch and begin to feed on the body's tissues.[6] Maggot activity, typically confined to natural orifices, and masses under the skin, causes the skin to slip, and hair to detach from the skin.[9] Maggot feeding, and the accumulation of gases within the body, eventually leads to post-mortem skin ruptures which will then further allow purging of gases and fluids into the surrounding environment.[8] Ruptures in the skin allow oxygen to re-enter the body and provide more surface area for the development of fly larvae and the activity of aerobic microorganisms.[11] The purging of gases and fluids results in the strong distinctive odors associated with decay.[6]

Active decay

Active decay is characterized by the period of greatest mass loss. This loss occurs as a result of both the voracious feeding of maggots and the purging of decomposition fluids into the surrounding environment.[11] The purged fluids accumulate around the body and create a cadaver decomposition island (CDI). Liquefaction of tissues and disintegration become apparent during this time and strong odors persist.[6] The end of active decay is signaled by the migration of maggots away from the body to pupate.[8]

Advanced decay

Decomposition is largely inhibited during advanced decay due to the loss of readily available cadaveric material.[11] Insect activity is also reduced during this stage.[9] When the carcass is located on soil, the area surrounding it will show evidence of vegetation death.[11] The CDI surrounding the carcass will display an increase in soil carbon and nutrients, such as phosphorus, potassium, calcium, and magnesium;[8] changes in pH; and a significant increase in soil nitrogen.[13]


During the dry/remains stage, the resurgence of plant growth around the CDI may occur and is a sign that the nutrients present in the surrounding soil have not yet returned to their normal levels.[11] All that remains of the cadaver at this stage is dry skin, cartilage, and bones,[6] which will become dry and bleached if exposed to the elements.[9] If all soft tissue is removed from the cadaver, it is referred to as completely skeletonized, but if only portions of the bones are exposed, it is referred to as partially skeletonised.[14]

Plant decomposition



Food decomposition

Main article: Meat spoilage


Importance to forensics



Factors affecting decomposition

Exposure to the elements







Artificial preservation


Environmental preservation





See also


  1. Water Quality Vocabulary. IShaO 6107-6:1994.
  2. "Biotic decomposition". Water Words Dictionary (WWD).
  3. González Medina A, González Herrera L, Perotti MA, Jiménez Ríos G (2013). "Occurrence of Poecilochirus austroasiaticus (Acari: Parasitidae) in forensic autopsies and its application on postmortem interval estimation". Exp.Appl.Acarol. 59 (3): 297–305. doi:10.1007/s10493-012-9606-1.
  4. Braig, Henk R.; Perotti, M. Alejandra (2009). "Carcases and mites". Experimental and Applied Acarology. 49 (1–2): 45–84. doi:10.1007/s10493-009-9287-6.
  5. González Medina A, Soriano Hernando Ó, Jiménez Ríos G (2015). "The Use of the Developmental Rate of the Aquatic Midge Chironomus riparius (Diptera, Chironomidae) in the Assessment of the Postsubmersion Interval". J.Forensic.Sci. 60 (3): 822–826. doi:10.1111/1556-4029.12707.
  6. 1 2 3 4 5 6 Payne, J.A. (1965). "A summer carrion study of the baby pig sus scrofa Linnaeus". Ecology. 46 (5): 592–602. doi:10.2307/1934999.
  7. Forbes, S.L. (2008). "Decomposition Chemistry in a Burial Environment". In M. Tibbett; D.O. Carter. Soil Analysis in Forensic Taphonomy. CRC Press. pp. 203–223. ISBN 1-4200-6991-8.
  8. 1 2 3 4 5 Carter D.O., Yellowlees; D., Tibbett M. (2007). "Cadaver decomposition in terrestrial ecosystems". Naturwissenschaften. 94 (1): 12–24. doi:10.1007/s00114-006-0159-1. PMID 17091303.
  9. 1 2 3 4 5 Janaway R.C., Percival S.L., Wilson A.S. (2009). "Decomposition of Human Remains". In Percival, S.L. Microbiology and Aging. Springer Science + Business. pp. 13–334. ISBN 1-58829-640-7.
  10. Knight, Bernard (1991). Forensic pathology. Oxford University Press. ISBN 0-19-520903-6.
  11. 1 2 3 4 5 6 7 Carter D.O.; Tibbett M. (2008). "Cadaver Decomposition and Soil: Processes". In M. Tibbett; D.O. Carter. Soil Analysis in Forensic Taphonomy. CRC Press. pp. 29–51. ISBN 1-4200-6991-8.
  12. Pinheiro, J. (2006). "Decay Process of a Cadaver". In A. Schmidt; E. Cumha; J. Pinheiro. Forensic Anthropology and Medicine. Humana Press. pp. 85–116. ISBN 1-58829-824-8.
  13. Vass A.A.; Bass W.M.; volt J.D.; Foss J.E.; Ammons J.T. (1992). "Time since death determinations of human cadavers using soil solution". Journal of Forensic Sciences. 37 (5): 1236–1253. PMID 1402750.
  14. Dent B.B.; Forbes S.L.; Stuart B.H. "Review of human decomposition processes in soil". Environmental Geology. 45: 576–585. doi:10.1007/s00254-003-0913-z.
  15. Filipiak, Michał; Sobczyk, Łukasz; Weiner, January (2016-04-09). "Fungal Transformation of Tree Stumps into a Suitable Resource for Xylophagous Beetles via Changes in Elemental Ratios". Insects. 7 (2): 13. doi:10.3390/insects7020013.
  16. 1 2 Filipiak, Michał; Weiner, January (2016-09-01). "Nutritional dynamics during the development of xylophagous beetles related to changes in the stoichiometry of 11 elements". Physiological Entomology: n/a–n/a. doi:10.1111/phen.12168. ISSN 1365-3032.
  17. Smith, KGV. (1987). A Manual of Forensic Entomology. Cornell Univ. Pr. p. 464. ISBN 0-8014-1927-1.
  18. Kulshrestha P, Satpathy DK (2001). "Use of beetles in forensic entomology". Forensic Sci. Int. 120 (1–2): 15–17. doi:10.1016/S0379-0738(01)00410-8. PMID 11457603.
  19. Schmitt, A.; Cunha, E.; Pinheiro, J. (2006). Forensic Anthropology and Medicine: Complementary Sciences From Recovery to Cause of Death. Humana Press. p. 464. ISBN 1-58829-824-8.
  20. Haglund, WD.; Sorg, MH. (1996). Forensic Taphonomy: The Postmortem Fate of Human Remains. CRC Press. p. 636. ISBN 0-8493-9434-1.
  21. Quigley, C. (1998). Modern Mummies: The Preservation of the Human Body in the Twentieth Century. McFarland. pp. 213–214. ISBN 0-7864-0492-2.
  22. Clark, Josh. "How can a corpse be incorruptible?". HowStuffWorks.
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Preceded by
Stages of human development
Succeeded by