A "body farm" at the foot of the Blue Mountains has made a number of important discoveries in the research of human cadaver decomposition since it became operational in 2016.
The AFTER site (Australian Facility for Taphonomic Experimental Research) at Yarramundi is the only facility of its type in the Southern Hemisphere, and was launched by the University of Technology (UTS) to observe and research the decay of human corpses.
Dr Maiken Ueland, postdoctoral research associate and deputy director of the project, said there are currently 74 human bodies on the site in various stages of decomposition, and the team did the best they could to make every body donation count.
One of the first discoveries they made was about pig carcasses, and the fact that they behaved differently from human bodies when decomposing.
"Pigs have traditionally been used a lot in taphonomic research, but we didn't know if they were true models for humans," Dr Ueland said.
"We were using pigs a lot before humans, so we wanted to see if they behaved in the same way. We followed their decomposition over different seasons, and what we found was how they were decomposing visually was quite different.
"Pigs decomposed very 'textbook-like' - the whole body at the same stage. But humans have 'differential decomposition', where one part of the body, say, the head, would look a lot more decomposed than, say, another body part like the leg.
"So it's much more challenging with humans to find the time of death."
A study by a Central Queensland University honours student, Alyson Wilson, has revealed different parts of the body - including facial features and hands - "move" during different stages of decomposition, as the body mummifies and the ligaments dry out. Ms Wilson has tracked a donor body via a timelapse camera over 17 months as part of her study.
"This knowledge could be significant in unexplained death investigations," she said.
Another finding was to do with the odour of the bodies, which the team tracks and analyses back in their lab at UTS in Sydney.
"We found that the odour was very different between pigs and humans, which means we can't use pigs to train cadaver detection dogs," said Dr Ueland.
She said one of the most important findings the team had made was to do with mummification - which is when the tissue becomes dark, dry and leathery, and prevents the decomposition process.
"We saw that happening a lot for the human remains. That will influence the time-since-death estimate," she said.
"We used to think mummification of tissue types happened in very specific environments, but in Sydney we're seeing it happens at all different seasons and times of year.
"That was quite shocking for us when we saw it - we were not expecting that whatsoever."
Apart from UTS, the AFTERS project has 16 other partner organisations, including other universities, forensics agencies, and law enforcement agencies.
Dr Euland said research at the site was multi-faceted. The team looks at how they can better find missing persons, techniques for working out the time of death, and techniques for body identification: "We're already seeing great results and we've been able to help the police directly with case work."
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