Non-human bones in forensic casework: not such a trivial problem.

When bones are submitted to mortuaries significant time and resources from both police and anthropologists are required, even if they are subsequently determined to be non-human. A survey of non-human bone casework was made in order to determine the scope of this problem and the different bone types being assessed. This study used data from nine years of casework at the NSW Department of Forensic Medicine (DOFM), Sydney. It analyzed the number of non-human cases that were assessed, the types of animals represented in these bones, the bone elements found, their condition and their location when found. By 2016, over 70% of skeletal cases handled each year by the Sydney DOFM were non-human. The most common animal remains were sheep and cattle, and the skeletal elements appearing in the greatest number of cases were vertebrae, followed by femora and tibiae. Skull fragments were rare. Slightly more cases were found on the surface rather than buried. Fragmentation might have been expected to contribute to difficulties in identifying bones, but in fact 32% of cases consisted of complete bones only. This study shows a very high proportion of non-human forensic casework in the Sydney region. Data presented in this study may prove useful in designing training workshops in non-human bone identification.