Discrimination of mongoose hair from domestic cattle hair, human hair, and synthetic fiber using FTIR spectroscopy and chemometric analysis: a rapid, cost-effective, and field-deployable tool for wildlife forensics†

Abstract

Mongoose hair is used to prepare fine brushes, which increases the demand for mongooses to be poached from the wild and brutally bludgeoned to death. Mongooses were listed as Schedule I species under the Indian Wildlife (Protection) Act 1972. Species identification of wildlife case-related samples is necessary to convict a person under this legislation. Microscopy and DNA-based techniques are commonly used to identify mongoose hair in seized brushes. However, in painting brushes, the roots, and the lower part of the hair are mostly trimmed, and only the upper part is used to make the brushes. In addition, brushes are often prepared with mixed hair from mongoose, domestic cattle, human hair, and synthetic fibre. Therefore, the identification of mongoose hair by microscopy and DNA-based techniques is restricted due to the lack of complete strands of hair and the absence of hair roots. Therefore, there is an urgent need to develop an alternative methodology for the identification of mongoose hair from seized articles. FTIR spectroscopy for forensic analysis has gained significant attention over the years because of its sensitivity, specificity, and non-destructive nature. The present study aimed to discriminate Indian grey mongoose (Herpestes edwardsii) hair from domestic cattle hair (domestic water buffalo and domestic cow), human hair, and synthetic fiber based on their chemical composition using FTIR spectroscopy and chemometric analysis. We have taken hair from four individuals for each species, namely Indian grey mongoose, domestic cattle, human hair, and synthetic fibre. The FTIR spectrum was recorded, and partial least-squares discriminant analysis (PLS-DA) was used to discriminate hair and synthetic fiber. The established PLS-DA model showed an R-square value and an RMSE (root mean square error) value of 0.9 and 0.13 respectively. Our preliminary findings have shown that FTIR spectroscopy combined with chemometrics can quickly discriminate Indian grey mongoose hair, domestic cattle hair, human hair, and synthetic fiber, providing crucial evidence for judicial proceedings.