1. Centre for Social Learning and Cognitive Evolution, School of Psychology and Neuroscience, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, UK
2. Department of Zoology, University of Oxford, Oxford, UK
3. Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
4. Sorbonne Université, CNRS, Institut des Systèmes Intelligents et de Robotique, ISIR, 75005 Paris, France
5. Centre for Social Learning and Cognitive Evolution, and Sea Mammal Research Unit, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, UK
6. Centre for Language Evolution, University of Edinburgh, Edinburgh, UK