Sexual dimorphism in echolocation pulse parameters of the CF-FM bat, Hipposideros pratti

Background: Previous studies of sexual dimorphism in the echolocation pulses of the constant frequency-frequency modulating (CF-FM) bat have been mainly concentrated on the difference in the frequency of the CF component of the predominant second harmonic while neglected other pulse parameters. However, recent studies have shown that other pulse parameters of the predominant second harmonic are also biologically significant to the bat hunting. To complement and advance these studies, we have examined sexual dimorphism of multiple parameters (e.g., duration, frequency, bandwidth of the FM component, and repetition rate of emitted pulses) of the echolocation pulses of the CF-FM bat, Hipposideros pratti. Results: Our studies of the predominant second harmonic show that on average the male bat has higher frequency of the CF component, wider FM bandwidth, and higher pulse repetition rate while the female bat has longer duration of the CF and FM components. Conclusions: These observations suggest that bats may potentially use this sexual dimorphism in echolocation pulse parameters for social communication and species and sex identification.