Forensic taphonomy in a cold climate region: A field study in central Alberta and a potential new method of determining time since death

This study represents the first analysis of taphonomic processes relevant to forensic investigations from a cold climate region, with a three phase research design that incorporates historical record reviews, animal analogy decomposition field studies, and search strategy field experimentation. Results of this study provide background for preliminary research and development of a histological method of estimating time since death.; In phase one, two separate record surveys were conducted at the Office of the Chief Medical Examiner in Edmonton, Alberta. The first examined cold weather decay rates; the second focused on cases involving hanging as the cause of death, with particular emphasis on outdoor and decomposed cases.; In phase two, a 20 month field study examining decomposition and scavenging was undertaken at two research facilities in the Edmonton area. Domestic pigs (Sus scrofa) were used as models for humans and were allowed to decay naturally under daily observation. Significant findings presented are: (1) the effects of carcass size on decay rates in shaded and sun exposed carrion; (2) observations that postmortem insect activity may mimic perimortem sexual assault clothing patterns; and (3) methods of identifying bird scavenging in fleshed and dry remains. Comparison of field study observations with record review results and case studies assesses the validity of animal analogues in human decomposition studies.; Results of both the field study and record reviews reveal a high incidence of animal scavenging in this region. Disarticulation and dispersal of remains by animals, combined with heavy snowfalls, confound search and recovery of remains and require innovative search strategies. In phase three, the results of field trials using specially trained "cadaver" dogs suggest that they are highly effective in locating dispersed human remains, particularly in snow.; Regional factors such as cold weather and intense animal scavenging render entomological methods of estimating time since death (TSD) ineffective. Preliminary investigations into a new histological method of determining TSD, which may prove less environmentally sensitive, are presented. Autolytic and putrefactive changes to the proteoglycans and Type II collagen of the nucleus pulposus of lumbar intervertebral discs may serve as indicators of postmortem interval.