How dead pigs can help nail killers
It is surprisingly difficult to find a place in Cape Town to leave a 60kg pig to rot. It cannot be close to water, in a residential area or anywhere near agricultural land – there are certain biohazard requirements.
It also has to be secure, so that none of the accompanying R46 000-worth of weather-monitoring equipment is stolen.
“This has been the most difficult part of my project,” says Devin Finaughty, a PhD candidate at the University of Cape Town (UCT).
Finaughty is investigating how human bodies decompose in the Cape, and a pig’s body is the closest to an actual human body when the latter can’t be used. He is quick to point out that his project has undergone rigorous ethical clearance.
We are sitting at the Rhodes Memorial Tea Garden, and overhead the mercurial Cape weather cannot decide whether it wants to rain.
Behind us, an eavesdropping elderly couple is torn between curiosity and disgust as we talk about dead bodies washing up on beaches, the life cycle of maggots and the bloating of corpses in a vlei.
Belinda Speed, another UCT PhD candidate investigating human decomposition, stirs her tea and pulls her cardigan closer around her.
“When we get bodies [in forensic pathology laboratories] that are decomposing, the main questions are: Who is it and how long have they been dead?” she says.
This is what Speed and Finaughty have set out to investigate: Finaughty on land and Speed in the turbulent Cape seas.
Bodies decompose differently, depending on the environment that they are in, and this information is necessary to determine a time of death and, if foul play is suspected, to find the person responsible.
“The decomposition process is extremely varied and there are various factors that influence how a body decomposes,” says Dr Jolandie Myburgh, a senior technical assistant and lecturer at the University of Pretoria’s Forensic Anthropology Research Centre.
These factors include the humidity of the region, and the types of insects and animal scavengers in the area, among others.
From our vantage point at the Rhodes Memorial, we have a panoramic view from the Cape Flats through to the Helderberg and Hottentots-Holland mountains. The landscape is vivid under the heavy grey clouds. In the distance, the Indian and Atlantic oceans crash into each other.
Right now, somewhere in that landscape, there are four dead pigs spread over 10 acres in “a secure, private location on the Cape Flats”. Their carcasses are lying inside galvanised steel cages and Finaughty goes out to the sites daily to weigh them.
Weight loss over time is an indicator of the rate of decomposition, and he uses this information, in conjunction with the weather data, to model how the bodies decompose.
This is particularly important for an area like the Cape, which is a unique biome with endemic animals and plants.
“Because of the mountain, Cape Town has seven biogeoclimatic zones, so a body found on Table Mountain will decompose at a different rate to one in a forested kloof or the Cape Flats,” he says.
In False Bay, Speed’s pig is suspended in a stainless steel cage and a camera light flashes periodically in the murky water. She chuckles: “red romans seem to love flashing lights, so there are lots of photos of red romans.”
Unlike Finaughty’s cage, which is a metal mesh, Speed’s looks more like a 1.7m x 1.6m x 1m prison cell. She starts off explaining the cage with her hands, but soon takes out her cellphone to show me pictures of it and a photo of a red roman.
It is blurry in murky water. “Mine has large bars, so that sharks can’t take a bite of it [the pig].”
Known as “pig lady” and sometimes “Babe” by the research diving unit, Speed says: “Because of the different bays and coastlines, we’ve had cases where pieces of human bodies and bones wash up on the beach.”
Her research aims to fill in many of the blanks about what happens to human bodies after they drown or are thrown or fall into the seas surrounding the Cape.
The area is unique because of the meeting of the two oceans. This affects what happens to a body, from the temperature of the water, its oxygen levels and salt content to how deep it is and how far the body is from the shore.
Knowing the extent to which these factors determine body decomposition will help forensic services and the police determine how long the person has been in the water.
“I will be overjoyed if I can fit a pig into a wet suit,” Speed says. She laughs at my surprise. “That is the kind of cases we’re getting – and a wet suit preserves the body in an amazing way. Animals can’t get into the wet suit and small fish can’t chew through.”
These small animals – both on land and in water – are pivotal to the decomposition process.
Finaughty’s work focuses on the insects that drive putrefaction.
There are internal decomposers, principally the bacteria in the digestive gut, as well as external insects and scavengers.
“[We] often talk about how the climate influences the rate of decomposition, but climate does it indirectly … [for example in terms of] the timing of flies depositing new eggs and the amount of bacteria growth,” Finaughty says.
“Yes, you can pull out individual variables, but if you want to make inferences about the system as a whole, you need to look at the whole system.”
Finaughty and Speed’s research adds to the work that has already been done on human body decomposition in the Cape.
“Currently, we only have data on decomposition patterns in Gauteng and the Cape,” says the University of Pretoria’s Myburgh, whose master’s thesis was on postmortem intervals in South Africa.
There are many different climates and environments in South Africa. “Ideally,” she says, “we would like to have data from all the various regions in South Africa so we can compare the body found to local data, which will minimise the degree of error from using decomposition data from a region with a completely different type of environment.”