Text and Data Mining valid from 2018-05-02
Received: 5 November 2017
Revised: 16 April 2018
Accepted: 22 April 2018
First Online: 2 May 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: All applicable international, national and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted. The study was approved by the joint animal ethics committee of the Zoo Leipzig and Max Planck Institute for Evolutionary Anthropology, Leipzig. Research was non-invasive and strictly adhered to the legal requirements of Germany. Animal husbandry and research complied with the “EAZA Minimum Standards for the Accommodation and Care of Animals in Zoos and Aquaria”, the “WAZA Ethical Guidelines for the Conduct of Research on Animals by Zoos and Aquariums” and the “Guidelines for the Treatment of Animals in Behavioural Research and Teaching” of the Association for the Study of Animal Behaviour.