Rise of the machines: Integrating technology with playback experiments to study cetacean social cognition in the wild

Cetaceans represent an evolutionary peak in terms of their cognitive capacities, complex communication systems and their structured, multilevel societies. However, the difficulty of observing their behaviour underwater means that studying whale and dolphin sociality in the wild poses some significant methodological challenges. Traditionally, playback experiments have been used to explore aspects of communication and cognition in whales and dolphins, particularly with trained animals under human care. However, while these studies have provided major breakthroughs in our understanding of cetacean social cognition, it is difficult to know whether these findings generalize to wild animals. In recent years, new state-of-the-art technology (drones and non-invasive sound and movement tags) have revolutionized the field of marine mammal behaviour, providing unparalleled information on the fine-scale behaviour of individuals in the wild. Here, we review the state of the field, combining published studies with our own extensive experience, to demonstrate how these new technologies fundamentally change the behavioural metrics that we are able to measure; allowing us to move from categorical observations to quantifying fine-scale changes in movement, activity and vocal behaviour. We discuss how conducting playback experiments alongside these new technologies combines rigorous experimental design with strong ecological validity and increased reproducibility and can be adapted for many social species, setting the standard for high-calibre, field-based experiments that explore animal social cognition in the wild.