Nonhuman Versus Human Remains
Although most Forensic Anthropologist Forensic Anthropology" href="/forensic-4/how-to-find-a-forensic-anthropologist.html">forensic anthropologists can easily distinguish intact, well-preserved human remains from those of nonhumans, fragmentary or otherwise altered material can be challenging. Detailed knowledge of human skeletal anatomy is usually sufficient to recognize that evidence is consistent with a human origin. The more precise opinion that remains are of human origin (could not be anything else) requires some recognition of the many other materials that can mimic the human condition. With the reality that molecular approaches potentially offer positive identification from minute bits of evidence, forensic anthropologists can expect to see increasing frequencies of submission of such evidence. Since the molecular procedures are costly and
time-consuming, an initial determination by the anthropologist of human vs. nonhuman can be important.
Such determinations usually rely on the experience of the anthropologist, supplemented by comparative collections. Other experts, especially zooarchaeologists or other naturalists, may need to be consulted. In my experience, microscopic examination can provide important diagnostic information. Examination of small evidence with a high-quality dissecting-type microscope (I currently use a Carl Zeiss SV 11 Stereomicroscope with photographic capability) allows clear viewing of morphological surface details that facilitate diagnosis. With fragmentary evidence, the examination of the visible internal surface may reveal helpful aspects of structure.
For especially difficult fragments, it may be desirable to prepare thin sections for even more detailed microscopic study (see Robling and Stout, this volume). In particular, the osteon organization may present a nonhuman pattern (Ubelaker, 1999e). Although human/ nonhuman differences in bone histology are recognized in the literature, more research is needed to clarify the distribution of these differences throughout the skeleton and among different species (Enlow, 1962, 1963; Enlow and Brown, 1956, 1957, 1958; Foote, 1916; Mulhern and Ubelaker, 2001, 2003; Ubelaker, 1999e).
If soft tissues are sufficiently preserved, they may provide additional clues on human/ nonhuman status. Hair analysis or serological techniques may be able to clarify whether remains are of human origin and perhaps identify species, genus, and so on. Both of these approaches have proven to be useful in determining that some forensic cases of submitted cranial remains represented calves with hydro-cephaly rather than human infants (Ubelaker et al., 1991). In this forensic application, extracts were prepared from desiccated soft tissue associated with the specimens. Double diffusion test methods were employed using the extract and antibodies of bovine, deer, horse, sheep, swine, and human. A precipitin line formed in the presence of antibovine serum, which with additional testing contributed to the final diagnosis that the remains represented calves with hydrocephaly. Hair examination and cranial morphology also contributed diagnostic information.
For extremely fragmentary and / or environmentally compromised material, even recognition if bone or tooth is present can be difficult. For such cases, scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) can produce diagnostic results. The spectra revealed in such analyses allow identification of constituent elements and their relative proportions. This information can facilitate identification if bone or tooth is present when compared with a relevant spectra database of known materials (Ubelaker et al., 2002b). Such analysis does not allow differentiation of human fragments from those of other animals, however. For such cases, protein radio immuno-assay (pRIA) analysis will distinguish between humans and nonhumans and even identify nonhuman fragments to the family represented (Ubelaker et al., 2004).
Post a comment