About the Authors

Bridget M. Waller

bridget.waller@port.ac.uk

Affiliation Centre for Comparative and Evolutionary Psychology, University of Portsmouth, Portsmouth, Hampshire, United Kingdom

Kate Peirce

Affiliation Centre for Comparative and Evolutionary Psychology, University of Portsmouth, Portsmouth, Hampshire, United Kingdom

Cátia C. Caeiro

Affiliation Centre for Comparative and Evolutionary Psychology, University of Portsmouth, Portsmouth, Hampshire, United Kingdom

Linda Scheider

Affiliation Department of Psychology, Freie Universität Berlin, Berlin, Germany

Anne M. Burrows

Affiliations Department of Physical Therapy, Duquesne University, Pittsburgh, United States of America, Department of Anthropology, University of Pittsburgh, Pittsburgh, United States of America

Sandra McCune

Affiliation WALTHAM®, Centre for Pet Nutrition, Leicestershire, United Kingdom

Juliane Kaminski

Affiliation Centre for Comparative and Evolutionary Psychology, University of Portsmouth, Portsmouth, Hampshire, United Kingdom

Competing Interests

The authors declare that author SM is an employee (Research Manager) of WALTHAM, a division of Mars Inc. All other authors have declared that no competing interests exist. This does not alter their adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: BMW AMB JK. Performed the experiments: KP CCC LS. Analyzed the data: BMW. Contributed reagents/materials/analysis tools: AMB. Wrote the paper: BMW JK. Assisted with study design: SM.