Vocalization of Tomistoma schlegelii and Gavialis gangeticus

We analysed 159 distress calls of five individuals of T. schlegelii for temporal parameters and obtained spectral parameters in 137 of these calls. Analyses of G. gangeticus were based on 39 distress calls of three individuals, of which all could be analysed for temporal and spectral parameters. Our results document differences in the call structure of both species. Distress calls of T. schlegelii show numerous harmonics, whereas extensive pulse trains are present in G. gangeticus. In the latter, longer call durations and longer intervals between calls resulted in lower call repetition rates. Dominant frequencies of T. schlegelii are higher than in G. gangeticus. T. schlegelii specimens showed a negative correlation of increasing body size with decreasing dominant frequencies. Distress call durations increased with body size. T. schlegelii distress calls share only minor structural features with distress calls of G. gangeticus.