Abstract:
During the past several years, non-invasive monitoring of steroid metabolites in faeces of elephants has
become an increasingly popular technique to generate more information about the causal relationship
between hormones and behaviour in both living elephant species. This is important knowledge which
can be used to optimise local conservation and wildlife management by finding new strategies for
better elephant population management and control. In this context, however, information about an
actual involvement of the hypothalamic-pituitary-adrenal axis during assumable stressful events is
still limited, especially for wildlife populations. One difficulty in discovering such information is
often the lack of reliable data for hormone baseline levels. Therefore, the aim of this study was to
determine baseline concentrations of faecal glucocorticoid metabolites that could be expected within
age classes and between seasons in African elephants (Loxodonta africana) in the Kruger National
Park (KNP ). A total of 374 faecal samples were collected from randomly located family herds in the
southern KNP between May 2002 and August 2005. The samples were analysed for immunoreactive
concentrations of faecal glucocorticoid metabolites using a validated enzyme immunoassay for
3α,11oxo-cortisol metabolites (3α,11oxo-CM). All samples were grouped according to the estimated
age class of the subject using a field method based on bolus diameter, and regarding the ecological
season collected. No significant differences in faecal 3α,11oxo-CM concentrations were found across
age classes (H3 = 7.54; p = 0.057), but the mean 3α,11oxo-CM concentration of samples collected in the
dry season (n = 196) was significantly higher than in the wet season (n = 178) (u = 15206.50; p = 0.032),
which indicates a possible physiological stress situation due to a decline in food quantity and quality.
The information generated in this study represents a reliable data set for baseline concentrations of
faecal glucocorticoid metabolites for elephants within the KNP and can be used to measure the stressrelated
effects of translocations, management actions and the impact of chosen land use activities.
