Great Himalayan Leaf-Nosed Bats Produce Different Territorial Calls to Respond to Sympatric Species and Non-Living Objects

SIMPLE SUMMARY: Many animals produce keep-out signals to keep intruders from entering their territories. Studies have shown that bats produce territorial calls to defend the conspecifics intrusion. However, it remains unknown whether bats can adjust their territorial calls in response to different types of intruders, such as heterospecifics or non-living objects. We simulated the process of territory defense in male great Himalayan leaf-nosed bats toward two sympatric species and four non-living objects to investigate their acoustic responses. Bats displayed different acoustic responses for different types of intruders, suggesting that territorial calls of male great Himalayan leaf-nosed bats may convey emotional state information when the bats respond to invasion by sympatric species or non-living objects. Our results are valuable for understanding animal cognition and interactions among bat species from an acoustic perspective. ABSTRACT: Territorial signals are important for reducing the cost of territory defense. Normally, male animals will produce keep-out signals to repel intruders from entering their territory. However, there is currently no evidence that bats can adjust their territorial calls to respond differently to sympatric species or non-living objects. In this study, we simulated the process of territory defense in male Great Himalayan leaf-nosed bats (Hipposideros armiger) toward two sympatric species (Hipposideros pratti and Rhinolophus sinicus) and four different non-living objects (a fur specimen of H. armiger, a bat model, a speaker, and a speaker with playback of H. armiger echolocation calls) to investigate their acoustic responses. There were significant differences in the territorial call complexity, syllable rate, and syllable ratio produced by H. armiger under the different experimental conditions. Our results confirmed that bats can adjust their territorial calls to respond to different sympatric species and non-living objects. The results will further our understanding of animal cognition and interactions among bat species from an acoustic perspective.