Scientific Working Group for Forensic Anthropology (SWGANTH)

Taphonomic Observations

Issue Date: 06/12/2013

Revision 0

TAPHONOMIC OBSERVATIONS IN THE POSTMORTEM INTERVAL

1.0 Principle, Spirit and Intent

The identification and correct interpretation of taphonomic alterations of human remains 

can assist with the reconstruction of postmortem events and the estimation of the 

postmortem interval (PMI; also known as time since death, TSD). A thorough and 

systematic examination of the evidence is essential for the identification of taphonomic 

features, recording their presence, and interpreting their significance.

2.0 Purpose and Scope

These guidelines recommend best practices for evaluating taphonomic influences on 

human remains relative to their environmental context. Taphonomic analysis often 

involves a multidisciplinary approach (including, for example, entomological or soil 

science analysis) for a more informed interpretation. Practitioners of forensic 

anthropology should implement these guidelines to the extent applicable, practical and 

appropriate. In the absence of specific guidelines or in the case of conflicting procedures, 

the principle, spirit and intent should be met. 

3.0 General Principles

Taphonomy focuses on understanding and documenting the various postmortem 

processes associated with decomposition as well as those processes (both natural and 

cultural or intentional) that interact with hard tissue and associated evidence. 

Taphonomy is used to evaluate postmortem alteration to human remains and to estimate 

PMI. Forensic anthropologists can contribute to the PMI estimate at any stage during the 

decomposition process. 

Thus, taphonomic observations can assist the forensic anthropologist by:

Estimating PMI.

Differentiating postmortem events from ante-mortem and peri-mortem events.

Determining medico-legal significance.
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4.0 Best Practices

4.1 Taphonomic alterations

Taphonomic processes have a wide range of observable effects on evidence, both soft and 

hard tissues. While the below list is not all inclusive, these represent areas that should be 

considered during an examination of both hard/bony and soft tissues:

Abiotic agents and effects, such as

o Weathering

 Mechanical/physical

Colluvial/Fluvial/Eolian transport (rolling, etc.)

Freeze/thaw cycles

Sun-bleaching, etc.

 Chemical

Pedogenic/subsurface

Surface chemical weathering

Harsh chemical damage related to erosion of cortical tissue (acids 

or bases)

o Thermal events, such as

 Soot or smoke-marking

 Calcined bones or teeth

 Melted or burned non-biological evidence.

Biotic agents and events:

o Decomposition processes, such as

 Autolysis

 Putrefaction

o Rodent, carnivore, or other scavengers (i.e., gnawing, chewing, etc.)

o Aquatic vertebrates/invertebrates/coral, etc.

o Trampling

o Insect/boring activity

o Root etching and root destruction

Anthropogenic effects, such as

o Trophy skulls (e.g., painting, carvings, wax, etc.)

o Anatomical specimens

o Cremation

o Religious practices (Santeria, Palo Mayombe, Moncado, etc.)

o Purposeful mutilation

o Accidental damage done during recovery excavation (excavation tool 

marks, mechanical excavation equipment, etc.)
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4.2 Postmortem Interval Estimation 

An accurate estimation of PMI may be critical to the death investigation and is often

based on scene contexts as well as associated evidence collected during the recovery 

phase. A body is subject to a wide spectrum of complex biotic and abiotic taphonomic

processes. The involvement of multiple specialists during the recovery phases is optimal; 

however, the anthropologist should be familiar with recommended collection and 

preservation strategies, so that if necessary, evidence may be submitted to other analysts 

at a later date. 

A variety of descriptive decomposition systems have been developed by forensic 

anthropologists as well as researchers in other forensic disciplines. In general, these 

descriptive systems use a series of phases to describe the decomposition process; these 

systems and phases, while comparable, vary based on different environmental and 

decompositional context. For example, scoring systems have been devised to quantify 

decomposition. The forensic anthropologist should consider using these to describe the 

condition of a body, and reference to its stage of decomposition and/or its total body 

score. Additionally, for accurate PMI estimation, the anthropologist should select the 

most appropriate methods based on the most similar physical and depositional 

environments.

Transition from one phase to the next is heavily influenced by a number of different 

factors that may accelerate or impede the progression between stages. The observed 

factors that influence the rates of decomposition should be described in bench notes and 

the anthropology report.

To that end, the variables that influence decomposition should be documented and may 

include:

Ecological and pedological characteristics, such as:

o Outdoor terrestrial

 Temperature and humidity

 Burial substrate, burial depth, ecosystem (e.g., pasture, park, 

wooded), oxygen content, etc.

 Soils: type, texture, moisture content, chemistry (i.e., C, N, P, 

pH, conductivity, etc.)

 Shade, sun, elevation

 Weather and seasonal observations (e.g., humidity; 

maximum/minimum daily temperature, rainfall, etc.);

 Insect and scavenger activity

o Indoor terrestrial

 Location: (e.g. barn, house - carpeted or hard floor, car, etc.);

 Temperature and humidity

 Insect and scavenger activity

o Aquatic (e.g. creek, marsh, swamp, river, lake, ocean, etc.) 

 water pH, temperature, depth;

 potential decomposer population;
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Age, body size estimations

Physical condition of the remains, including clothing and trauma;

Cultural modifications can include:

o Intentional mutilations

o Unintentional damage, such as hand excavation methodology or heavy 

machinery used during recovery operations.

Human interaction as well as natural movement of a body can affect the depositional 

environment, such that remains may be moved from one type of environment to another. 

Given that the recovery and PMI estimations may be a multi-agency and 

multidisciplinary process, the anthropologist should be conscientious of other evidence 

that may be collected. In fact, the forensic anthropologist may have to coordinate efforts

of these experts. The forensic anthropologist can obtain a more accurate PMI and 

understanding the taphonomic sequences by using this multidisciplinary approach. The 

anthropologist should be familiar with other disciplines’ recommended collection and 

preservation strategies, so that appropriate evidence may be submitted to an appropriate 

analyst at a later date.

5.0 Unacceptable Practices

The follow practices are considered unacceptable and should be avoided:

Making a PMI estimate without consideration of the taphonomic 

context/depositional environment.

Interpreting taphonomic events as trauma.

Using terms such as “trauma” and “injury” to describe traumatic 

events/defects. 

Reporting overly precise or insupportable PMI estimates.

Making interpretive statements that are beyond the forensic expertise of the 

analyst.

Application to remains should be more descriptive rather than interpretive in 

nature (e.g., suspected paint should be describe as color or pigment instead of 

suspected material; suspected gold application should be described as yellowcolored metal, etc.).

Interpreting taphonomic signatures outside of one’s area of forensic expertise.