A rapid chemical odour profiling method for the identification of rhinoceros horns

Illegal poaching causes great harm to species diversity and conservation. A vast amount of money is involved in the trade of illegal or forged animal parts worldwide. In many cases, the suspected animal part is unidentifiable and requires costly and invasive laboratory analysis such as isotopic fingerprinting or DNA testing. The lack of rapid and accurate methods to identify wildlife parts at the point of detection represents a major hindrance in the enforcement and prosecution of wildlife trafficking. The ability of wildlife detector dogs to alert to different wildlife species demonstrates that there is a detectable difference in scent profile of illegally traded animal parts. This difference was exploited to develop a rapid, non-invasive screening method for distinguishing rhinoceros horns of different species. The method involved the collection of volatile organic compounds (VOC) by headspace solid-phase microextraction (HS-SPME) and analysis by comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GC×GC-TOFMS). It was hypothesised that the use of the specific odour profile as a screening method could separate and differentiate geographic origin or exploit the difference in diets of different species within a family (such as white rhinoceros and black rhinoceros from the Rhinocerotidae family). Known black and white rhinoceros horn samples were analysed using HS-SPME-GC×GC-TOFMS and multivariate statistics were applied to identify groupings in the data set. The black rhinoceros horn samples were distinctly different from the white rhinoceros horn samples. This demonstrated that seized rhinoceros horn samples can be identified based on their distinct odour profiles. The chemical odour profiling method has great potential as a rapid and non-invasive screening method in order to combat and track illegal trafficking of wildlife parts.