Skeleton research provides insight into culture of Caribbean Indians
Archaeologist Hayley Mickleburgh studies how bodies decompose. This helps with the reconstruction of changes in the burial rituals of Caribbean Indians.
Did colonisation result in a different burial culture?
Mickleburgh researches what happened in the Caribbean region after the arrival of the Spanish in 1492. It was common practice for Indians to be buried in a foetal position, in shallow or even open graves. The question is to what extent this practice changed when the region was colonised. Mickleburgh: ‘We know that some of the indigenous people were buried differently in the course of time. In a Christian way: with the arms crossed over the chest. I am looking at whether other, possibly more subtle, changes took place. But to be able to understand the condition and position of the skeletons that have been found, we first have to have a clear idea how a body decomposes completely naturally.’
Little known about skeleton stage
Thanks to forensic research, a lot is known about the early stage while a corpse still has tissue. But much less is known about the stage when it has become a skeleton. Mickleburgh is the first archaeologist to study the process of decomposition. She does this in Texas in the US, in what’s known as a ‘body farm’. At this facility corpses are examined for forensic research and science. Mickleburgh has at her disposal five donations, or bodies – the deceased determine while still alive that their body can be used for research at the body farm.
From body to skeleton
Mickleburgh first had to take a decomposition training course before starting her work. Of the five donated corpses she put three in open graves and buried the other two. Three were placed in foetal position and one sitting. In the warm Texan climate after only four months, all that will be left of a body left the open air will be the skeleton. Mickleburgh photographed the changes every day and made 3D models of them. By placing the models over one another she could see precisely what changes had taken place.
The bones of the skeleton can also shift as a result of the processes involved in natural decomposition, and are then found in a non-anatomical relationship. If the hands are placed on the abdomen, the bones of the hands can fall into the backbone, once the soft tissue of the abdomen has disappeared. Shifts can of course also be the result of other factors, such as animal activity if a large animal has disturbed the grave. Mickleburgh tries to avoid animals - apart from insects – as much as possible. ‘I want to exclude all possible other factors that could cause a change in the grave so that I can map out the disintegration of the skeleton. This will allow archaeologists to distinguish better the effects of human intervention in a grave.’
More research needed
In the autumn of 2016 Mickleburgh will be exhuming the bodies she has buried in order to analyse them. However, this does not mean that her research is completed. Mickleburgh: ‘A pilot study of five bodies is not enough to construct a model. But this experiment has confirmed the value of this kind of research for archaeology and it has generated some new insights.’
With a seated body, for example, the connection halfway along the neck is the first to be released when the skull falls. With a supine body, the neck vertebrae stay connected for longer and the first break starts between the head and the first neck vertebra. ‘It may seem only logical that gravity can make such a difference, but until now the same model was used for interpreting skeletons in different positions.’
Mickleburgh hopes that a new subsidy will allow her to carry out more research with 30 donations. She also wants to analyse the photographic data from around a thousand bodies that other body farms are making available.
Archaeologists and forensic researchers are very interested in her research findings that are to be published in specialist journals. ‘It is very useful to know what natural factors determine the eventual condition and position of a skeleton. That can help you assess whether a body has been disturbed.’
A lot of publicity
This research has attracted a lot of attention in the media. Everyone wants to know how a young archaeologist – just 31 years old – can do this kind of research. Mickleburgh: ‘These experiments have enormous scientific value and I really don’t find it gruesome or grisly at all. Maybe that’s because I know that these people decided while they were still alive that they wanted to make this contribution to scientific research. We treat their special donations very respectfully.’
How rapidly a body decomposes depends on the temperature and the humidity, and also on the level of insect activity. Mickleburgh can only partly replicate the conditions of the Caribbean region. In Texas it is around 40 degrees in summer. The temperature in the Caribbean is higher, and it’s also more humid there. A body left in direct sunlight and heat can mummify (dry out) very quickly, because bacteria and insects such as maggots thrive less well in a dry and warm climate. Natural mummification is prevalent at the decomposition facility in Texas, where it is possible to study this process in the past.