A study investigating and quantifying synergistic effects of vertebrate and invertebrate scavengers, clothing, and sharp force trauma on decomposition in the Table Mountain region, Cape Town, South Africa (2024-2026).

What is the research about?

This research aims to replicate forensic death investigations on Table Mountain to assist the Police to improve identification rates, create forensic leads and to better estimate time-since death. This will be accomplished by understanding the combined effects of vertebrate (e.g., Cape grey mongoose) and invertebrate (e.g., insects mostly flies, beetles, ants, and wasps) scavengers on the rate and pattern of decomposition of clothed adult-sized pigs that have been traumatised.

Table Mountain National Park (TMNP) is chosen because as a World Heritage Site it attracts hundreds of thousands of local and international tourists and visitors each year. When there are lots of people, there are, unfortunately, some accidents and casualties within and around the park, which often end up as medico-legal death investigations at the Salt River Mortuary (SRM)/Observatory Forensic Pathology Institute (OFPI). The second ecological zone with the highest number of forensic anthropology cases attended to by UCT’s Forensic Anthropology Cape Town (FACT) service provider are from TMNP and local conservation sites. We lack data for TMNP, and the data from the Cape Flats, where we have been conducting decomposition studies for the past 7 years, are not applicable to this area given the dramatic environmental differences created by the presence of the Table Mountain range.

Why conduct experimental decomposition research in the first place? Can’t we answer these questions by looking at forensic cases where the human bodies are already decomposed? Why does it even matter?

Retrospectively analysing decomposition cases from local mortuaries is a possible route to better understand local decomposition processes. However, the comprehensiveness of our understanding will always be limited by the quality of data, and a lot of contextual information is often missing from cases, for many reasons – many beyond our control. Medico-legal death investigations often provide a snapshot of the decomposition process, rather than a robust understanding of how the process plays out in different circumstances. We absolutely need the latter to be able to build models of decomposition that facilitate forensic investigative leads, estimating the time-since-death and reconstructing the circumstances around a person’s death.

Being able to generate accurate decomposition information in the Western Cape Province/City of Cape Town/TMNP will contribute significantly and positively to the work of our local Forensic Pathology Services based at SRM/OFPI and the South African Police Services with regards to case resolution as explained above; facilitating both social and criminal justice for the benefit and safety of all South Africans, and especially the most vulnerable members of our society; as well as, providing much needed familial closure and giving dignity in death to the decedent. This is the impetus for this research program.

What is all the big equipment and apparatus in the field for? Do they make this research unique?

Yes! This research is the first of its kind in South Africa to implement a transdisciplinary approach for understanding the role of vertebrate and invertebrate scavengers on the rate of decomposition of clothed and traumatised bodies. It is one of the world’s first synergistic investigations of decomposition, and the first to utilise an automated data collection approach (the big machines you see in the field) – putting UCT-based and proudly African research on the international map for its innovation, and ensuring we are developing African solutions for African challenges.

Why are we interested in vertebrate scavengers?

Vertebrate scavengers (e.g., Cape grey mongoose, porcupine, and caracal) are well-known to significantly impact the rate and pattern of decomposition. In Cape Town, previous research on the Cape Flats has shown that the Cape grey mongoose is a major scavenger of decomposing bodies. Not only can their activity change the rate and pattern of decomposition which can complicate our efforts to determine time-since-death, but they will carry off and scatter parts of the body into the surrounding area. Scattering can hamper body recovery, which can perpetuate the anguish already suffered by the family of the decedent. We need to recover the whole body where possible and do our best to accurately estimate the time-since-death to help police narrow the pool of missing persons they are searching and confirm or refute suspect alibies. For these reasons, understanding scavenging activities in the various habitats they inhabit in Cape Town is crucial.

Why are we interested in invertebrate scavengers (insects)?

Insects play a significant role in decomposition, and knowledge regarding their lifecycles and behaviour can help the police establish time-since-death and season of death – the central focus of forensic entomology. We don’t know how they interact with vertebrate scavengers, and if clothing and trauma will change their activity, behaviour, and/or development.

Why do we use pigs in our research?

In South Africa, we are not legally permitted to use donated human bodies for decomposition research. Pig bodies offer a well-established reliable alternative, at least when we are seeking to establish baseline data, as we are in this study. These pigs were destined for human consumption and were approved for use in this study under UCT FHS Animal Ethics Committee approval #023_031.

Equally important, most medico-legal death investigations in South Africa are clothed to some degree (as opposed to being unclothed). Therefore, in this research study, the pigs are clothed to replicate this forensic realism and to further investigate how this variable (i.e., clothing) affects decomposition rate in Cape Town especially in the Table Mountain region, to better estimate time-since-death and to help reconstruct the events that led to the victim’s death and the deposition of their body.

Why are we interested in clothed bodies that have been traumatised?

South Africa has a high murder rate.  In the Western Cape, sharp force trauma (e.g., stabbing, slashing), has been identified as one of the leading causes of murder. Research on sharp force trauma, both in South Africa and abroad, has provided conflicting results regarding the effect of sharp force trauma on the rate and pattern of decomposition. In general, trauma has been widely suggested to speed up the rate of decomposition by providing insects and other scavengers easier access to the soft tissues of the body and additional sites for bacteria infestation, and insect reproduction. However, other studies have suggested that there is no effect.

Therefore, in this research study, the pigs are not only clothed, but also traumatised to fully replicate what is obtainable in medico-legal investigations. By doing this, we will be able to examine how these two variables (i.e., clothing and trauma) interact and influence the decomposition rate in the Table Mountain region of the City of Cape Town. All of this will provide us with empirical baseline information that can improve the accuracy of our estimations of the time-since-death of the bodies of deceased individuals recovered within the region.

Who should I contact for more information?

The Principal Investigator for this research is Professor Victoria Gibbon, and the Field Directors are Dr Maximilian Spies and Dr Kara Adams  University of Cape Town. Please contact Prof. Gibbon  for further information or answers to any questions you might have.

See more information of Forensic Taphonomy research at UCT here