About the Authors

Angela S. Stoeger


Affiliation Department of Cognitive Biology, University of Vienna, Vienna, Austria

Gunnar Heilmann

Affiliation Gfai tech GmbH, Berlin, Germany

Matthias Zeppelzauer

Affiliation Institute for Software Technology and Interactive Systems, Vienna University of Technology, Vienna, Austria

André Ganswindt

Affiliations Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, Pretoria, South Africa, Section of Reproduction, Department of Production Animal Studies, University of Pretoria, Onderstepoort, South Africa

Sean Hensman

Affiliation Adventures with Elephants, Bela Bela, South Africa

Benjamin D. Charlton

Affiliation School of Psychology, University of Sussex, Brighton, United Kingdom

Competing Interests

Since two authors (Gunnar Heilman and Sean Hensman) are employed commercial companies the authors want to declare that they did not pay for using the equipment nor for doing research with the elephant at Bela Bela. Therefore, both companies had no financial interest concerning the research. The fact that these authors are employed by these companies does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: ASS GH. Performed the experiments: ASS GH SH AG. Analyzed the data: ASS MZ. Contributed reagents/materials/analysis tools: ASS MZ. Wrote the paper: ASS BDC.