Spies Maximilian J, Finaughty Devin A, Gibbon Victoria E
Department of Human Biology, University of Cape Town, Observatory, Cape Town, South Africa.
Department of Human Biology, University of Cape Town, Observatory, Cape Town, South Africa.
Forensic Sci Int. 2018 Sep;290:29-35. doi: 10.1016/j.forsciint.2018.06.015. Epub 2018 Jun 20.
The effect of vertebrate scavenging can drastically alter the rate of decomposition and cause skeletal scatter, which hinders human forensic recovery and identification. Patterns of scavenging, disarticulation and scatter in a forensic context are specific to different environments with no known data for South Africa. A better understanding of these patterns can increase the chances of full body recovery and improve identification of human remains. In this preliminary study, the effect of wild vertebrate scavenging on skeletal scatter was examined using a porcine model in the forensically significant thicketed Cape Flats Dune Strandveld habitat. This area is a densely populated part of Cape Town, which suffers from poor socioeconomic conditions and a high murder rate. Ethics was granted for the use of three small (∼20kg) domestic pig (Sus scrofa domesticus) carcasses as proxies for human decomposition. They were deployed in Delft, Cape Town, and observed by motion-activated cameras to record wild scavenger activity. One pig served as a control and was caged to prevent vertebrate but not invertebrate access; the other two served as experimental treatments. Scatter was recorded every second day by marking the location of skeletal elements and measuring the distance and angle from the centre of each deposition site. No scattering was observed in the control, but notable scattering patterns were observed in the experimental pigs due to Cape grey mongoose (Galerella pulverulenta) scavenging, the only vertebrate scavenger species observed. No clear pattern of scatter distance over time was followed. Scatter began in the skeletonisation phase (day 25-30), resulting in a maximum distance of 12.67m and scatter/search area of 504.32m. Mongoose-induced skeletal scatter followed a distinct pattern of movement into dense undergrowth, a previously unobserved behaviour and a key finding of this study. These results provide baseline data for sub-adult human scatter, or scatter of smaller components of an adult human skeleton, as demonstrated in the forensic case example provided. Knowledge is provided on locally relevant decomposition patterns and informs search methods for improved human skeletal recovery in forensic cases. There is scope for expansion of this study, with an investigation of seasonal effects, the interaction between invertebrate and vertebrate activity, as well as, the effect of clothing on scavenger access.
脊椎动物食腐行为的影响会极大地改变分解速度并导致骨骼散落，这会妨碍人类法医的尸体找回和身份鉴定。在法医背景下，食腐、关节分离和骨骼散落模式因不同环境而异，而南非尚无相关已知数据。更好地了解这些模式可以增加完整尸体找回的几率，并改善对人类遗骸的身份鉴定。在这项初步研究中，在具有法医意义的灌木丛丛生的开普平原沙丘草原栖息地，使用猪模型研究了野生脊椎动物食腐行为对骨骼散落的影响。该地区是开普敦人口密集的地区，社会经济条件差且谋杀率高。已获批伦理许可，使用三头小型（约20千克）家猪（Sus scrofa domesticus）尸体作为人类分解的替代物。它们被放置在开普敦的代尔夫特，并通过运动激活相机进行观察，以记录野生食腐动物的活动。一头猪作为对照，被关在笼子里以防止脊椎动物但不防止无脊椎动物接触；另外两头作为实验处理。每隔一天通过标记骨骼元素的位置并测量每个沉积位点中心的距离和角度来记录散落情况。对照中未观察到散落，但由于开普灰獴（Galerella pulverulenta）的食腐行为，在实验猪中观察到了明显的散落模式，开普灰獴是观察到的唯一脊椎动物食腐物种。随着时间的推移，没有观察到明显的散落距离模式。散落在骨骼化阶段（第25 - 30天）开始，最大距离为12.67米，散落/搜索面积为504.32平方米。獴引起的骨骼散落呈现出一种独特的模式，即向茂密的下层植被移动，这是一种以前未观察到的行为，也是本研究的一个关键发现。这些结果为亚成人尸体散落或成人骨骼较小部分的散落提供了基线数据，如所提供的法医案例所示。提供了关于当地相关分解模式的知识，并为法医案件中改进人类骨骼找回提供了搜索方法。本研究有扩展的空间，可以调查季节影响、无脊椎动物和脊椎动物活动之间的相互作用，以及衣物对食腐动物接触的影响。
