Yuri Shirane, Hokkaido Research Organization

Bear-inflicted human injuries and fatalities pose serious challenges to both public safety and bear conservation. Accurate identification of individual bears involved in severe incidents is essential for clarifying the causes of attacks and for making appropriate management decisions. Here, we report a case in which a single brown bear involved in two fatal attacks on humans was genetically identified using microsatellite analysis in Hokkaido, Japan. Following a fatal attack in 2021, hair samples collected near the victim were used for genetic profiling of the responsible bear. This profile was compared with those of 120 bears killed between 2021 and 2024 within the municipality where the 2021 incident occurred and in neighboring municipalities. The results indicated that the offending bear had not been removed during this period. In 2025, another fatal bear attack occurred in a residential area 2.5 km away from the 2021 incident site within the same town. Microsatellite analysis of bear hair samples collected from the victim revealed that this second incident was caused by the same individual bear identified in 2021. Furthermore, genetic comparison confirmed that the bear removed six days after the 2025 incident matched the genotype obtained from the hair sample. These cases emphasize that rapid and continuous sampling combined with DNA analysis is essential for managing severe human–bear conflicts. Such forensic genetic approaches enable accurate identification of problem individuals and support timely management decisions, including targeted removal following serious attacks. Moreover, genetic confirmation of the removal of the responsible bear plays a critical role in ensuring transparency of management actions and in restoring a sense of safety among local communities.