About the Authors

Ellen Evers

Affiliation Animal Ecology, Utrecht University, Utrecht, the Netherlands

Han de Vries

Affiliation Animal Ecology, Utrecht University, Utrecht, the Netherlands

Berry M. Spruijt

Affiliation Animal Ecology, Utrecht University, Utrecht, the Netherlands

Elisabeth H. M. Sterck

e.h.m.sterck@uu.nl

Affiliations Animal Ecology, Utrecht University, Utrecht, the Netherlands, Ethology Research, Biomedical Primate Research Center, Rijswijk, the Netherlands

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: EE HdV. Performed the experiments: EE. Analyzed the data: EE. Wrote the paper: EE HdV BS ES.