Royal Society University Research Fellow
Harold Mitchell 305
My broad research interests include animal culture, social learning, bioacoustics, and behavioural ecology. My main research focuses on cetaceans, and in particular the cultural transmission, vocal learning, and function of humpback whale song. I am also interested in vocal sequence analysis techniques, and using similarity in vocal displays to define population structures for conservation management.
Sexy singing: Cultural evolution and sexual selection in a complex song display
The role of sexual selection in signal evolution is a major topic of evolutionary research, not least in vocal displays such as song. Are some songs attractive because of who sings them, or do they have inherent qualities that make them attractive when sung by anyone? Despite decades of research on sexual selection, this is not always clear. In humpback whales, only males sing, and thousands of males can rapidly replace their song by learning a new song in as little as two months, a feat unparalleled in the animal kingdom. Song presents an interplay between cultural evolution and sexual selection; however, we have little understanding of how the most complex vocal display in the animal kingdom is governed by these selective forces. This project seeks to explore the underlying selective forces interacting and governing various aspects of humpback whales song. These fundamental concepts are central to advancing our understanding of the evolution of complex communication in human and non-human animals, as cetaceans represent a unique example on the continuum of cultural complexity. Follow along with PhD students Franca Eichenberger, Sara Niksic and me as we investigate song function.
Central and eastern South Pacific song transmission
Male humpbacks sing an elaborate, hierarchically structured vocal display specific to their breeding population. Moreover, thousands of males can synchronously change their population-specific song to a new version introduced from a neighbouring population in as little as two months. This phenomenon, termed a ‘song revolution’, appears unparalleled in any other animal except humans. We have previously shown that songs pass repeatedly across the South Pacific, stepping between populations from east Australia in the west to French Polynesia in the east. Songs appear to originate from west Australia located in the Indian Ocean, representing a ~6,000 mile transmission. The vocal linkage between the Indian and South Pacific Ocean basins raises the question of how far a single song type can be transmitted. Follow along with PhD student Natalie Sinclair and me as we investigate whether song revolutions continue to spread into the eastern South Pacific.
Previous postdoctoral fellowships:
Newton International Fellowship (University of St Andrews)
Culture in whales: transmission of a complex display
Animal culture and social learning is a ground-breaking area of research, with growing evidence of cultural processes in primates, cetaceans, and birds. Humpback whale songs are one of the most startling examples of transmission of a cultural trait and social learning in any non-human animal. Recent work has demonstrated a clear pattern of complete population-wide changes that were replicated in multiple populations over a vast geographic region. The level and rate of change is unparalleled in the animal kingdom; humpback whales are thus excellent models for studying cultural evolution processes in non-humans. Research conducted during my Newton fellowship into song learning has revealed that humpback whales employ some of the same learning mechanisms as songbirds and humans when acquiring a new song, which we recently published in PNAS.
National Academy of Sciences (NRC) Postdoctoral Fellowship (Marine Mammal Lab, AFSC/NOAA)
Geographic variation in the dialects of Alaskan Arctic beluga populations
Populations of beluga seasonally migrate to summering areas within the Chukchi and Beaufort Seas. The aim of this study was to identify population-specific differences in call characteristics or dialects among the three populations of beluga (eastern Beaufort Sea, eastern Chukchi Sea and Norton Sound) that migrate annually to the Chukchi and Beaufort Seas, to provide baseline information for noise impact studies in the region. This work allowed previously unresolved population movements throughout the Alaskan region to be traced using fine-scale differences in spatio-temporal peaks in calling, and highlighted the successful application of acoustical studies to improve our understanding of stock structure for management and conservation in a region undergoing rapid climate change.
(source: symbiosis database)