Rates of self-directed behaviour and faecal glucocorticoid levels are not correlated in female wild olive baboons (Papio hamadryas anubis)

Abstract

Non-invasive methods to quantify components of stress in non-human animals rely typically on the use of physiological or behavioural measures. At the physiological level, stress is usually measured non-invasively in terms of faecal or urinary glucocorticoid output. A common group of behavioural measures used are self-directed behaviours (SDBs), which have been shown to be linked to anxiety, a subset of stress, although a number of authors have explicitly linked SDBs to stress more generally. Whether increased rates of SDBs are likely to be associated with increased faecal glucocorticoid ouput in wild mammals remains unclear. Here, for wild female olive baboons, we show no association between day-to-day changes in levels of SDB and cortisol metabolite excretion. We also show no relationship between long-term mean levels of these variables. We discuss several possible interpretations of our results, including the possibility that SDBs represent a behavioural coping mechanism, helping to ameliorate the physiological stress response.

Keywords::

• Anxiety
• auto-grooming
• captive welfare
• dominance rank
• female primates
• natural environment

Acknowledgements

The authors would like to thank Nigerian National Parks Service for permission to undertake research in GGNP. NCF/WWF-UK provided field logistical support. Bobbo Buba, Halidu Ilyusu, Helen Cross and Alejandra Pascual Garrido helped collect data in the field. Balbir Singh Josen provided lab assistance at Roehampton University. Changiz Mohiyeddini provided valuable discussion, in addition to advice on statistics. Lauren Brent, John Russell and five anonymous reviewers provided constructive criticism of the manuscript. Funding came from Roehampton University and The Leakey Trust. The Chester Zoo Nigeria Biodiversity Programme provided core funding for key Gashaka Primate Project infrastructure Baboon faecal samples were imported into the UK under license from DEFRA (license number AHZ/2537/2004/1). This is GPP publication number 69.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.