Taphonomic Study of Adult <em>Susscrofa domestica</em> in Equatorial Climate in Sarawak, Malaysia

Special Article - Forensic and Legal Medicine

Austin J Forensic Sci Criminol. 2017; 4(1): 1058.

Taphonomic Study of Adult Susscrofa domestica in Equatorial Climate in Sarawak, Malaysia

Ing TK, Ismail NA and Soon LP*

Department of Forensic Medicine, National Institute of Forensic Medicine, Malaysia

*Corresponding author: Lai Poh Soon, Department of Forensic Medicine, National Institute of Forensic Medicine Hospital Kuala Lumpur, Jalan Pahang, 50586 Kuala Lumpur, Malaysia

Received: February 07, 2017; Accepted: February 24, 2017; Published: March 10, 2017

Abstract

Taphonomic study is first time conducted in Sarawak, Malaysia. In this research model, two adults female Susscrofa domestica weighed 77 kg each are killed by machete at the heart region. Then, the bodies are put clothes made of pure cotton on to mimic the real human body with clothes. Pure cotton clothes is a favourite for Malaysia’s population due to hot and humid climate. Later on, the bodies are being placed in the separate location labelled A and B in jungle. Taphonomic changes is obeserved. All stages of decomposition like fresh stage, bloated stage, active decay stage, advanced decay stage and remains stage are observed and documented. Daily observation on both the bodies is conducted. The ambient temperature of surroundings, internal temperature of bodies, temperature of larvae mass, body surface temperature, soil surface temperature and humidity of air are recorded daily. Time for each stage of decomposition is determined. During the decomposition process, insects and larvae appeared in each stage of decomposition process are collected and preserved for reference. Photos and videos are taken for each subject throughout the research. The hot and humid climate in Sarawak accelerates the decomposition process. The time taken for both bodies to reach remains stage is nine days. Both the cotton clothes are still preserved by the end of research. As a conclusion, an equatorial climate is accelerating the decomposition process of body in Sarawak, Malaysia.

Keywords: Taphonomic study; Susscrofa domestica; Cotton clothes; Decomposition process; Equatorial climate

Introduction

Taphonomic study is a research which includes various discipline such as decomposition process, preservation, dispersion, buried and exposition of dead body [1]. Forensic taphonomy is an international endeavour which includes collecting the evidence in crime scene and interpretation of dead cases [2]. Forensic taphonomy is often linked with ecological aspect because carcass is considered as newly emerging microenvironment [3]. Taphonomic study is an actualistic research which shares common fundamental between traditional, paleontological taphonomy and forensic taphonomy [4]. Taphonomic study on adult Susscrofa domestica in humid climate in Malaysia is a study to mimic the real human body decomposition. In this study, cotton cloth is put onto the adult Susscrofa domestica due to the preference of Malaysian to wear sweat-absorbent material like cotton for daily dressing. Thus, it is highly possible to recover evidence of clothing material that is important to forensic investigation because in criminal cases clothing will normally be intact, but may be disturbed by taphonomic process [2]. Besides that, murder case is quite common and the body is usually dumped in the rural area or open field in jungle. Hence, the important thing is that we would like to find out the decomposition rate and taphonomic changes in order to deduce the post-mortem interval as well as estimation of time of death.

Apart from that, cadaver is the food source that will initiate the complex cycle of tropic phase like decomposition process, assimilation, and dispersion [5]. Cadaver also caused the chemical, temperature and soil composition changes of the environment [6,7]. Thus, taphonomic research is very dependent on the environmental factor and local condition such as atmosphere, lithosphere, biosphere, decomposition process, preservation technique and condition of buried [8]. During the decomposition process, cadaver is break down into smaller material and absorb into the soil, washed away by rain, eaten up by insects or evaporated into the air [2]. Taphonomic data is useful as forensic evidence to determine original death place, ways of transportation body, criminal activities, and post-mortem interval determination [8].

In Malaysia, there are several researches conducted to evaluate the insect succession pattern as well as decomposition process of pigs in palm oil plantation [9,10]. Malaysia is located in Equator. Equatorial climate in Malaysia contribute to high and stable temperature throughout the year. Annual mean temperature of Malaysia is 27.3 °C except Genting Highlands and Cameron Highlands which have the lower annual mean temperature of 18.6 °C [11].

The taphonomy study is conducted in small village known as Bintangor located in Sarawak, East Malaysia. This is the pioneer research of taphonomic study in Sarawak. In this research model, two female adults Susscrofa domestica weighed 77 kg each is selected due to its size that can resemble the adult human body. Susscrofa domestica as a human body surrogates is an acceptable manner for scientific research [2]. For the taphonomic study, adults Susscrofa domestica is used as analogue for human body due to its characteristic lack of fur, almost same weight with normal human body, and easily obtain from market [12-14]. Apart from that, the decomposition process for Susscrofa domestica is almost same with the human body. The decomposition time for each stage is almost same with human body under the same environment condition [13].

Hence, the taphonomic study of adult Susscrofa domestica in Equatorial climate in Bintangor, Sarawak can mimic the real decomposition process of human body. This pioneer taphonomic research can generate a complete set of data sheet which includes pattern of insect succession, post-mortem interval determination based on the decomposition rate, effects of cotton clothes on the decomposition process, effects of Equatorial climate on the research study and comparison of research study between West Malaysia and East Malaysia in the aspects of decomposition rate. The outcome of this study can benefit the enforcement body in the investigation of crime scene involved the human body as well as the researchers in this field. This study has obtained ethical clearance from Animal Ethics Committee of the National University of Malaysia.

Methodology

Two adults Susscrofa domestica carcasses weighing 77 kg each were used in this study. Both of them were killed by piercing at the heart region with machete. After that, both the carcasses were put on the pure cotton clothes. Later, the pigs were put on top of the jungle floor separately which labeled Site A and Site B. Bothe the sites are 120 meters away from each other. Fencing (120 cm×70 cm×48 cm) was provided to protect the carcasses from animals. This study was conducted in the morning of the month of May, which was taken as the first day in the jungle of Bintangor, Sarawak with Equitorial climate.

Observations were made for 26 days with 3 visits per day except first day. First visit was in the morning (8 a.m.), second visit was in the noon (12 p.m.) and third visit is afternoon (6 p.m.). First day observation was conducted 4 times (11 a.m., 1 p.m., 6 p.m., and 9 p.m.) to evaluate the changes of the carcass deeply. Climatological data such as ambient temperature and humidity were recorded for 26 days by using digital thermometer and hygrometer. Ground temperature, body surface temperature, internal temperature and maggot mass temperature were taken for each visit. Adult flies were caught by using sweep net. Some of the fly larvae were collected using forceps and put into ethyl alcohol 70% for preservation [15]. The specimens were processed for storage and kept as record in the Forensic Science Department, Faculty of Allied Health Sciences, and The National University of Malaysia.

Results

The air humidity in the jungle of Bintangor, Sarawak for the 26 days ranged from 69% to 93% (mean 83.54±6.21%) at site A while ranged from 73% to 95% (mean 85.27±6.00%) at site B. Three times of raining were recorded during the study (day-1, 9 and 13).

The ambient temperature ranged from 27.1°C to 32.4°C (mean 30.17±1.34°C) at site A while ranged from 27.0°C to 31.9°C (mean 29.85±1.32°C) at site B. Ground surface temperature recorded ranged from 26°C to 28°C (mean 27.38±1.32°C) at site A while ranged from 27°C to 31°C (mean 28.46±1.30°C) at site B.

Maggot mass temperature varied from 33°C to 48°C (mean 43.14±4.85°C) at site A while ranged from 28°C to 51°C (mean 42.4±7.79°C) at site B. Internal temperature ranged from 27°C to 50°C (mean 39.23±7.34°C) at site A while ranged from 27°C to 55°C (mean 37.73±8.27°C) at side B.

All of the decomposition processes were taken certain period of time. From the graph (Figure 1,2), there was a higher temperature of maggot mass temperature and internal temperature.