Abstract
Doug Cato’s research includes pioneering studies of the underwater acoustic environment surrounding Australia and numerous contributions to our understanding of marine mammal acoustic behavior. Moreover, his relaxed avuncular manner allowed him to assemble collaborations spanning disparate disciplines while mentoring the next generation of acoustics researchers in Australia. Throughout his career, Doug built bridges between underwater acoustics and animal bioacoustics, and between Australian and international researchers. This talk highlights two international collaborations applying signal processing techniques to humpback whale songs and leopard seal calling bouts. These projects estimated the information entropy and structure of the sequences of sounds in these marine mammal vocalizations. Comparing sliding window entropy estimates with Markov models supports Doug’s earlier observations that Australian humpback song follows the hierarchical structure proposed by Payne & McVay for North Atlantic humpbacks [Miksis-Olds et al., JASA, 2008]. The same comparison of entropy estimators for leopard seal calling bouts reveals that most of the sequential structure of in these animals’ calls is captured by Markov models.