Evidence that bottlenose dolphins can communicate with vocal signals to solve a cooperative task.

Stephanie L King,Kelly Jaakkola,Christina Mcmullen,Emily Guarino,Katy Donegan

doi:10.1098/rsos.202073

Abstract

Cooperation experiments have long been used to explore the cognition underlying animals' coordination towards a shared goal. While the ability to understand the need for a partner in a cooperative task has been demonstrated in a number of species, there has been far less focus on cooperation experiments that address the role of communication. In humans, cooperative efforts can be enhanced by physical synchrony, and coordination problems can be solved using spoken language. Indeed, human children adapt to complex coordination problems by communicating with vocal signals. Here, we investigate whether bottlenose dolphins can use vocal signals to coordinate their behaviour in a cooperative button-pressing task. The two dolphin dyads used in this study were significantly more likely to cooperate successfully when they used whistles prior to pressing their buttons, with whistling leading to shorter button press intervals and more successful trials. Whistle timing was important as the dolphins were significantly more likely to succeed if they pushed their buttons together after the last whistle, rather than pushing independently of whistle production. Bottlenose dolphins are well known for cooperating extensively in the wild, and while it remains to be seen how wild dolphins use communication to coordinate cooperation, our results reveal that at least some dolphins are capable of using vocal signals to facilitate the successful execution of coordinated, cooperative actions.

Highlights

Many animals are known to work together to perform cooperative tasks that require individuals to coordinate their behaviour in royalsocietypublishing.org/journal/rsos R
We examined the effect of whistles in two ways: we first assessed whether the presence of whistles influenced trial success; and for those trials with whistles, whether the number of whistles affected trial success. The time between their button presses was significantly shorter in trials where they whistled, with whistle presence leading to significantly more successes, i.e. the dolphins were more likely to press their buttons within 1 s of each other if they whistled than if they did not
The results show that the two bottlenose dolphin dyads used in this study are capable of using vocal signals to facilitate the successful execution of coordinated, cooperative actions

Summary

Introduction

Many animals are known to work together to perform cooperative tasks that require individuals to coordinate their behaviour in royalsocietypublishing.org/journal/rsos R. Examples can be found across the animal kingdom, where individuals have been 2 shown to work together in order to improve foraging efficiency (e.g. ants [1], wild-dogs [2], sailfish [3] and humpback whales [4]), dominate in inter-group contests (e.g. dolphins [5], lions [6], chimpanzees [7] and mongooses [8]) and enhance reproductive success (e.g. baboons [9] and dolphins [5]) Such tasks require the coordinated performance of two or more individuals and, in many animals, communication appears to facilitate this coordination. Our understanding of how individuals use and share information during such coordinated group tasks remains limited [10]

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Conclusion