Active predation by brown rats (Rattus norvegicus) on bats at urban mass hibernacula in Northern Germany: Conservation and one health implications

This study is the first to document systematic predation by Rattus norvegicus on bats at urban hibernacula hosting several thousand individuals in Europe. Using infrared video surveillance and thermal imaging at two major sites in Northern Germany (Segeberg and Lüneburg Kalkberg) used predominantly by Myotis species, we observed aerial interception and ground-based hunting strategies targeting swarming bats. The predation behavior highlights the remarkable manipulative abilities and behavioral plasticity of brown rats in urban ecosystems. Our findings suggest significant additional mortality risks for bat populations at mass hibernacula and raise concerns about potential pathogen exchange between two major wildlife reservoirs. We recommend targeted rodent management strategies to mitigate conservation and public health risks in line with One Health approaches.