How Do Bodies Decompose?

Cape Town has consistently been one of the metropolitan regions in South Africa with the highest murder rates. It has more than double the national average, and is currently ranked second overall and 16th worldwide. Many victims are discovered only after their bodies have decomposed, burned, or been exposed to the elements. That makes identification difficult and delays justice.

Each year, more than 3,500 unnatural deaths, including murders and accidents, are handled by the city’s Observatory Forensic Pathology Institute. Around 9% remain unidentified. That’s hundreds of families left without answers. We asked Victoria Gibbon and colleagues about their work in forensic taphonomy.

What is the role of forensic taphonomists?

In death, we all decompose in the same general way. But understanding the nuances, especially those introduced by unnatural deaths, requires forensic taphonomy – the science of understanding how bodies break down. Every decomposition process is unique. It is shaped by everything around us: what we’re wearing, how we’re buried and what animals and insects might find us first.

Forensic taphonomists study all these variables and more, specialising in the recovery and analysis of human remains in the context of their environment. They play a vital role in death investigations involving unidentified persons, which requires specialised expertise in the human body and environment. There is a close working relationship with police and pathologists who hold the responsibility for identification and circumstances of death.

Imagine: a body is uncovered amid the sand and scrub of Cape Town’s coastline. By the time it’s found, the remains are in an advanced state of decomposition – identity unclear, the timeline murky. Understanding decomposition helps to determine how long someone has been dead, which can support identification, narrow down missing persons lists, or confirm (or contradict) witness accounts. It’s essential, delicate and some could say, grim work.

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Forensic taphonomists’ expertise lies in understanding how bodies decompose under different conditions and how that process can reveal time-since-death, potential trauma, and ultimately, identity. Forensic taphonomists answer questions like: Who was this person? How long have they been there? And what happened to them? Their work sits at the intersection of science, justice and innovation. Because in the end, forensic science is about justice, not just science.

One of the main challenges in forensic taphonomy is that many of the global standards were developed in countries with very different climates and ecological systems. So, they are not representative of South Africa. Cape Town’s internationally unique microclimates, soil types and scavenger populations don’t align neatly with existing models.

To produce locally relevant data, researchers need to observe how decomposition actually happens in these settings. In South Africa, the legislation does not allow forensic taphonomists to study the decomposition of human bodies donated to medical science for research, as happens elsewhere in the world. Therefore they most frequently study the decomposition of adult domestic pigs as internationally accepted models for human decomposition. Pigs have numerous biological similarities to humans that are important for decomposition.

Initial decomposition studies in the Western Cape more than a decade ago began by examining unclothed bodies to establish baseline data. But as it turns out, that’s not what most cases look like. In reality, most deceased persons are clothed, and usually discovered alone. This mismatch prompted a shift.

What have you done differently in your research?

More realistic, single-body, clothed studies were needed. That meant smaller sample sizes, longer timelines, and greater data accuracy. But it leads to findings that are actually applicable in local forensic work.

We innovated, creating a world-first automated data collection machine to tackle the challenge of consistency and cost-effective, reliable long-term monitoring. It tracks decomposition in real-time, continuously and remotely. As bodies lose mass (due to water evaporation, insect activity, or tissue breakdown), the machine logs the weight changes, providing high-resolution data on the progression of decomposition. This removes the subjectivity of human observation. It allows researchers to collect standardised information across multiple cases and environments, simultaneously. It is solar-powered and transmits data remotely via cell phone networks, meaning it can be deployed anywhere we need to establish data for.

Our system has tracked in detail how tissues dry out beneath the skin. This can help reconstruct the time since death by linking drying patterns to environmental conditions and weather.

In addition to weighing decomposing bodies, our system provides continuous power to two motion-activated infrared trail cameras.

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One camera trap is positioned directly above the body; the other is alongside the body. Together, these cameras record photos and videos of the decomposition process, giving us detailed insight into the activities of the animals that come to eat and otherwise interact with the decomposing body.

This machine offers precision, reliability and adaptability. It transforms how decomposition can be studied.

What’s next?

This technological innovation isn’t just a local solution. The team aims to provide a means by which researchers from different countries can share results that are directly comparable. These will form the basis for a global taphonomic data network: a collaborative platform for researchers to gain insights into decomposition as it plays out across geographies, environments and case types.

The hope is that this network will allow forensic anthropologists to adapt decomposition estimates to local contexts while contributing to an international evidence base.

Collectively, our research innovations may help produce more accurate case outcomes, that are admissible in court, and capable of providing justice for victims. Assistance with case resolution means restoring the identities of those who might otherwise have been lost to justice and history.

Victoria Gibbon receives funding from National Research Foundation of South Africa. She is affiliated with The University of Cape Town.

Devin Alexander Finaughty receives funding from the Oppenheimer Memorial Trust. He is affiliated with the University of the Witwatersrand and the Wildlife Forensic Academy.

Kara Adams is affiliated with the University of Cape Town.

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