Emerging Researchers National (ERN) Conference

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Analysis of Animal Hair Samples Using Microscopic Techniques for the Forensic Assessment of Individual Identification Characteristics

Undergraduate #84
Discipline: Biological Sciences
Subcategory: Education

Shannon James - Fort Valley State University
Co-Author(s): Reginald B. Mims


Animal hair can be a major contributor when leading investigators to a breakthrough in solving a crime. It is very easily transferred and can be present on pet owners or farm workers; the victim or the suspect could have unknowingly left hair on the other linking the suspect to the place of the crime. Human and animal hair shaft shows similarities in having an outer covering (cuticle) consisting of scales; an intermediate layer (cortex) which contains the pigment granules imparting the color to hair and an inner core (medulla). Though these are similar morphological features, the scale pattern provides distinguishing characteristics between animal and human hairs. The scales of an animal’s hair show many distinctions such as coronal (crown- like) and spinous patterns, whereas the human hair scale pattern is of imbricate (flattened) type. At least ten measurements were performed during the morphometric analysis of the hair shaft, medullary diameter, cortex thickness, and scale length. Cuticle scale patterns were investigated using the rapid nail polish method. The guard hair shaft diameter, the medullary index and scale length were measured using image analysis software. A spinous cuticle pattern was found in the rat (fancy hooded), rabbit, cat (calico), and deer. The coronal cuticle pattern was seen in the mouse (fancy), cat (tabby), and the hamster. The medullary cavity index in all the animals investigated in this study was one half or greater except for the female fancy mouse where it was lee than half (0.32). The data obtained in this study suggest that the microscopic analysis of the animal hairs is a valuable diagnostic tool for species identification.

Funder Acknowledgement(s): NSF HRD HBCU-UP Targeted #1238789

Faculty Advisor: Seema Dhir,

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This material is based upon work supported by the National Science Foundation (NSF) under Grant No. DUE-1930047. Any opinions, findings, interpretations, conclusions or recommendations expressed in this material are those of its authors and do not represent the views of the AAAS Board of Directors, the Council of AAAS, AAAS’ membership or the National Science Foundation.