Origin traceability of Amur tiger hair using stable isotope ratio mass spectrometry

As an endangered species, the Amur tiger (Panthera tigris altaica) faces severe threats to its survival from illegal poaching and cross-border smuggling, which also undermines biodiversity. Traceability detection of Amur tigers is crucial for combating such crimes; however, current traceability efforts primarily rely on witness testimony, lacking scientific and technological support. To address this gap, this study pioneers the application of Isotope Ratio Mass Spectrometry (IRMS) in the field of forensic science, focusing on Amur tiger hair to develop a traceability technology. Hair samples were collected from 20 Amur tigers across 10 zoos in different regions of China, and their stable isotope abundance values were analyzed. The results showed no significant differences in δ¹³C, δ¹⁵N, δ²H, and δ¹⁸O values among different hair samples from the same individual. For different individuals in the same zoo, the isotope abundance values of their hair were dominated by the feeding conditions, with only minor variations. Additionally, the isotope abundance values of Amur tiger hair from different zoos exhibited characteristic distributions. The reasons for the differences were discussed, and the Amur tiger hairs from different zoos were differentiated. The stable isotope traceability technology for Amur tiger hair established in this study provides key technical support for combating illegal poaching and trade of Amur tigers in the forensic science field. It also offers a reference for the traceability detection of other endangered species.