Body Farms Explained: How Scientists Study Human Decomposition

Warning: while this article talks about the stages of decomposition of the Human Body, it contains no images of human remains.

So it’s Halloween, let’s go for a spooky theme for this month’s Forensic Science topic. There’s nothing more creepy than bodies or skeletons. Picture this: A group of people are sitting in a room listening to a lecture. The title is How your Cat is Trying to Kill You. We all know our furry friends are out to rule the world, but they still need us to open the tins of cat food, don’t they? Well, the lecture gets interesting when the lecturer decides to answer the question ‘Will our cat eat us after we are dead?’ She brings up a grainy photograph on the screen and the first reaction of most people in the hall is ‘Aww! Look at those ickle clawsy wawsies!’ Only then do we notice the claws are stuck into the arm of a body located on a body farm. It’s true. I was in the room looking at those darling little claws (Pepper, 2024). Sadly, the important part of the anecdote is not the cat, but the spine-chilling body farm. The light tone of this introduction notwithstanding, body farms provide essential forensic research into decomposition.

What is a body farm?

I’ve touched on decomposition in both the Forensic Entomology and Investigating an Underwater Crime Scene articles, but how do criminologists know how decomposition progresses? Since the late 1980s, researchers have studied human corpses in controlled outdoor situations, to better understand the processes of decay. The bodies of people are left unburied to decompose naturally in a variety of environments. Tests and observations are performed on the decaying bodies, recording the progression of decomposition. Image 1 shows similar tests performed on cattle carcasses.

The information provided is vital for forensic science to give reasonable certainty in knowing the date from death or Post Mortem Interval (PMI). It probably won’t surprise you to learn there is considerable uneasiness about the use of human bodies for this type of study (Thomson, 2023).

A Short History of Body Farms

As with many forensic techniques, body farms have less than forty years of history; the first one opened in 1987. More accurately, body farms are Anthropology Research Facilities. The nickname ‘body farm’ comes from the Patricia Cornwall novel. The uneasiness over the use of human remains to study decomposition led to the use of pigs instead. Pigs share similar characteristics to humans, including the way hair grows and body mass. The paths of decomposition can be studied on pigs, but not the timing of human decay. The differences in eating habits and body shape mean that pigs decompose faster than humans (The Mob Museum, 2023).

In 1977, Dr William Bass made a mistake in determining the time from death.

Case Study

In 1977, police caught what they thought were murderers attempting to hide a body in an American Civil War grave. When approached, Dr Bass gave an opinion that the body had been dead for under a year. Unfortunately, the remains had been embalmed and buried in an iron coffin. Instead of a new victim, the find was a 113-year-old body. The police had caught Grave Robbers, not Murderers.

Rather than cover up his mistake, Dr Bass decided he needed more research. In 1981, he began his study into decomposition. In 1987 he set up his first forensic research facility, which has aided many law enforcement officers to bring murders to justice (Bonezones, 2018). However, bodies decompose at different rates depending on the environment. After Dr Bass established this first facility, body farms have been started in places all over the world.

How does a body farm help work out date from death?

While pigs and other mammals help provide insights into decomposition, they have very little to say about the rate of decay of a human. Rabbits don’t go to the pub and get drunk. Pigs don’t wander into a burger bar and gorge on fast food. The habits of living creatures (including humans) are just one of the factors that determine the rate of decay. Even the environment the body is left in,  Whether it is wrapped or buried can influence the rate of decomposition (Banino, 2022).

How does a body left in woodland compare with one left in an open field in direct sunlight? Body farms are another way to continue the study of forensic entomology, refining the study of when various insects appear after death.

At a body farm, a corpse can be left in all these environments. The careful notes taken about each corpse can help law enforcement officers judge the date from death.

Is a body farm just about decomposition?

A body farm is more than just a place to study how bodies decompose. The Forensic Osteology Research Station at Western Carolina University allows the training of Cadaver dogs (Killgrove, 2015).

A little science

What scents do cadaver dogs pick up? Even human noses can pick up the rotting flesh scent of Cadaverine, as shown in image 2.

But there is also Putrescine, which is also the basis of bad breath, pictured in image 3.

Skatole and Indole make up the smell of faeces, but are also present on a corpse. Buried bodies give off more indole than those in the open air, while exposed bodies produce more acetone (Huang, 2017).

Additionally, the Forensic Anthropology Research Station in Texas has learned that bodies give off heat, and using drones with infrared cameras is a novel way to locate missing remains. The Southeast Texas Applied Forensic Science Facility of Sam Houston State University is studying how to identify the sex of the remains from fragments of the pelvic area (Killgrove, 2015).

Stages of Decomposition

Despite differences in environment, all bodies tend to go through certain stages. The gut of living creatures contains microbes of digestion. While living, the microbes do their job to digest the food that keeps life running.

Initial Decay

Externally the body may look intact, but inside the gut, those microbes that kept the organism alive,  now have no food, so they begin digesting the intestine wall and start on the internal organs (Australian Museum, 2020).

Microbes of Decomposition

Recently, three different body farms have studied the microbial composition of decay and found out that 20 microbes determine the process of animal and human decay. Even with differing environments, these microbes show up at precise intervals after death, making them a new indicator for ascertaining PMI (Colorado State University, 2024).

As mentioned in the Forensic Entomology article, blow flies show up almost immediately after death to lay their eggs (Knipe, 2023). Combining the fly’s lifecycle with this new microbe study increases the accuracy of determining PMI.

Putrefaction

Between four and ten days after death, anaerobic bacteria start to break down the cell walls releasing fluid into the surroundings. The drones used by the Forensic Anthropology Research Station in Texas can pick up what is known as a ‘Cadaver Decomposition Island’. This island is formed from the fluids released in this stage (Banino, 2022). Gases build up inside the body cavity and those attract predatory insects that feed on the blowfly maggots that hatched from the eggs laid in the first stage (Australian Museum, 2020).

Black Putrefaction

When the gases escape, the body flattens. This happens between ten and twenty days post-mortem. The muscles and skin become mushy and all exposed surfaces turn black. A foul smell of decay spreads out from the corpse. Now, parasitic wasps arrive to feed on the several generations of maggots that have lived on the rotting carcass.

Butyric Fermentation

The next stage happens up to fifty days post-mortem. The fluids have leaked away leaving a dried-out carcass. The maggots no longer find the food appetising, they prefer the softer stages of decay, and now beetles with hard chewing mouthparts are found on the body.

Skeletisation or Dry Decay

After anything up to a year, the flesh and hair are eaten away leaving only bones (Australian Museum, 2020).

Environmental factors also play into how a body decays. We all know that cold will retard decay, and heat speeds it up. But did you know that immersing a body in water initially slows the decay? This is probably because it is cool, and once the body is removed from water the decay is more rapid than if it had just been left in open air (Caruso, 2016).

The Ethics of Studying Human Decomposition

As I mentioned above, most of the early studies of decomposition were performed on pigs. Nevertheless, studying human remains is necessary even though it brings ethical considerations. Most people are dubious about studying humans so all the remains must be treated with respect. First of all, prior consent to scientific use must be obtained, which includes how long they can be used for the study and how the body should be treated after the study concludes. Some people may be happy to have their bones used in anatomy labs, while others may prefer burial or cremation. Equally, the people who work at the facility may have difficulty thinking about their work on humans and be desensitised to the care needed to remain respectful of the bodies. All of these things need to be taken into consideration when setting up a research facility of this type (Christofidis, 2023).

Conclusion

While there are ethical considerations about using human bodies in decomposition studies, it is vital work. Without the studies on cadavers, then law enforcement would still be making mistakes when dating human remains. If police officers have a reasonable idea of when someone died, then they have more chance of bringing the perpetrator of the crime to justice and giving the family of the deceased some closure. All of these are excellent reasons why the study of decompositions on body farms is crucial to help solve crime.

I have tried to limit the distressing images in this article, but if you would like to see those claws that had a lecture room go ‘Awww!’, then click on this link here. Scroll down to figure 5. Please be aware there are images of dead people in this paper.

References

Australian Museum. (2020). Stages of Decomposition. June 25. https://australian.museum/learn/science/stages-of-decomposition/

Banino, R. (2022). Down on the body farm: the gruesome, but vital forensic facility coming to the UK. BBC Science Focus. June 10. https://www.sciencefocus.com/the-human-body/body-farms

Bonezones. (2018). Dr William Bass. https://bonezones.com

Caruso, J. L. (2016). Decomposition Changes in Bodies Recovered from Water. Academic forensic pathology, 6(1), 19–27. https://doi.org/10.23907/2016.003

Christofidis, G. (2023). Body Farms: An Overview of Their Purpose in Forensic Science. AZO Lifesciences.  May 17. https://www.azolifesciences.com/article/Body-Farms3b-An-Overview-of-Their-Purpose-in-Forensic-Science.aspx

Colorado State University. (2024). New Study on Decomposing Microbes Could Help Transform Forensic Science. PhysOrg. Feb 12. https://phys.org/news/2024-02-decomposing-microbes-forensic-science.html

Huang, L. (2017). What Cadaver Dogs Really Sniff For In The Hunt For The Dead. Inverse. July 27. https://www.inverse.com/article/34350-cadaver-dogs-smell-death-corpse-police

Killgrove, K. (2015). The 6 ‘Body Farms’ Help Forensic Anthropologists Learn to Solve Crimes. Forbes. June 15. https://www.forbes.com/sites/kristinakillgrove/2015/06/10/these-six-body-farms-help-forensic-anthropologists-learn-to-solve-crimes/

Knipe, V. (2023). Crime-Solving Insects—Forensic Entomology. Mozart Cultures. May 5. https://mozartcultures.com/en/crime-solving-insects-forensic-entomology/

The Mob Museum. (2023). Body Farms Unravel The Mysteries Of Human Decomposition. National Museum of Organised Crime and Law Enforcement. May 26. https://themobmuseum.org/blog/body-farms-unravel-mysteries-of-human-decomposition/

Thomson, J. (2023). How Body Farms Are Helping Forensics Solve Murders. Newsweek. May 7. https://www.newsweek.com/body-farms-decomposing-bodies-forensic-science-murder-1798397

Pepper. (2024) How Your Cat is Trying to Kill You. August 12. World Science Fiction Convention Glasgow 2024. Glasgow SEC.

Images

Putrescene: Benjah-bmm27, Public domain, via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Putrescine-3D-balls.png

Cadaverene: Benjah-bmm27, Public domain, via Wikimedia Commons https://en.wikipedia.org/wiki/Cadaverine#/media/File:Cadaverine-3D-balls.png

Cattle decomposition on a body farm: Anil1956 at English Wikipedia, Public domain, via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Roma15.jpg

Buffalo head: Giles Laurent, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons https://commons.wikimedia.org/wiki/File:005_Decomposing_African_buffalo_skull_in_the_Serengeti_National_Park_(edit)_Photo_by_Giles_Laurent.jpg

Catlink https://onlinelibrary.wiley.com/doi/full/10.1111/1556-4029.14238