Introduction to Forensic Taphonomy

Forensic taphonomy is the study of what happens to a body between death and recovery. A large amount of forensic research focuses on trying to better understand taphonomic factors. Some of this research takes place in dedicated taphonomic research facilities, such as the famous Forensic Anthropology Center in Knoxville, Tennessee widely referred to as ‘The Body Farm’. Anthropological methods will work best when applied to bones that are well preserved. Also, skeletons are easier to recover from the ground if they are complete and in good condition. Unfortunately, this is not always the case. There are a wide range of factors that affect the quality and quantity of bone that is recovered in forensic investigations. We call these taphonomic factors. Copyright David Petts It is important to understand how these factors affect the body so that we can better interpret information about the body and the context of death and burial.

Intrinsic Factors

Some of the variation in how a body decomposes is to do with the person. This includes factors such as age-at-death, sex, and the presence of any pathology. For example, as part of the natural ageing process, we lose bone mass with increasing age. This is why elderly people are more likely to sustain broken bones when they fall over. This low bone mass can also affect preservation after death and burial, leading them to decay more quickly. Line drawing of the skeletons of an infant and adult female (Copyright Durham University) Infant bones can be more difficult to locate and recover than adult bones. Their bones are less completely mineralised, but often survive quite well, even for thousands of years. The key problem with infant bones is their small size, which makes them prone to disturbance in the ground, easy to miss at excavation, or frequently mistaken for animals. The picture below shows an infant skeleton being uncovered from a Roman site (c2000 years old) in Britain. The bones have survived well but note the damage to the skeleton due to later disturbance of the grave. An infant skeleton from a Roman site Pathological status is important. If someone has a condition that affects bone mass in any way then this will affect the survival of the bone in the ground. You will see a dramatic example in Week 4. Another example of this is the vertebrae below which show compression fractures (note that some vertebrae look flattened compared to others) and thinning of the bone due to osteoporosis. Although you can’t tell from the photograph, the bones shown are very light in weight, which also indicates a loss of bone mass. Copyright Durham University

Factors relating to the assailant

• An open injury can affect the speed of decomposition when a body is buried because the wound provides a means of entry for animals to attack the body.
• If a body has been put in a freezer then this will slow down decomposition (but not completely stop it). If the body then thaws out decomposition will speed up very rapidly.
• If a body is wrapped tightly in plastic prior to burial or disposal, this will slow down decomposition and will hinder animal scavenging of the remains as well as the impact of plants, insects and other disturbance. In fact, new research has shown that this impact can be used by forensic practitioners to preserve bodies where resources are limited.
• If multiple bodies are buried within a single grave then this will have an impact on the decomposition process and will also make the recording and recovery of the skeletons more complicated (we’ll explore this further in Week 6).
• Occasionally, bodies are deposited in very hard to reach areas, such as thrown down a well, or into a crevasse. Doing so not only serves to hide the body well, but it also complicates recovery of the remains (see Week 6 for an example).