Friendly foxes: the relationship between steroid hormones and social behaviour in a monogamous African canid

Abstract

Aside from some studies on cooperatively breeding species, we know little about the underlying endocrine mechanisms of social behaviour in the order Carnivora. We investigated the correlations between steroid hormones and social behaviour in a socially monogamous canid, the bat‐eared fox (Otocyon megalotis). We collected faecal and observational data over 15 and 22 months, respectively, from 14 wild bat‐eared foxes in the Kalahari Desert, South Africa. These data were used to describe the relationship between faecal hormone metabolite concentrations and social behaviour. Faecal androgen metabolite (fAM) concentration differed by sex and mating season and was positively associated with faecal glucocorticoid metabolite (fGCM) levels. Male foxes had substantially higher fAM concentrations (median: 9.99 μg g−1 org. content, IQR = 7.39–11.62 μg g−1 org. content) than females (median: 1.93 μg g−1 org. content, IQR = 1.68–2.56 μg g−1 org. content). Higher fAM concentrations were associated with more social tolerance in female but not male foxes. Concentrations of fAM were positively associated with rate of inter‐group encounters in female foxes. Furthermore, fAM concentrations were also positively associated with the overall rate of negative social interactions for females. Finally, fAM concentrations were positively associated with scent‐marking behaviour in male, but not female foxes. There was no association between fGCM concentrations and any of the observed social behaviours in male foxes. Female foxes had a negative relationship between fGCM concentration and marking behaviour as well as social tolerance. There was no difference in fGCM concentration between female (median: 0.19 μg g−1 org. content, IQR = 0.16–0.23 μg g−1 org. content) and male (median: 0.22 μg g−1 org. content, IQR = 0.19–0.31 μg g−1 org. content) foxes. Our study is the first to describe the endocrine correlates of aggressive and affiliative behaviour in the monogamous bat‐eared fox. Androgens play an important role in mating behaviour in monomorphic, monogamous species where females might drive sexual selection.

Changes in Fecal Glucocorticoid Metabolites in Captive Coyotes (Canis latrans): Influence of Gender, Time, and Reproductive Status

“…Similar to other species, we found different fGCM levels between females and males, with females exhibiting greater concentrations and higher variability than males [ 24 , 49 , 50 , 51 ]; although one study found little variability between sexes [ 23 ]. Trends across sexes are generally not consistent among carnivores and are likely influenced by food quantity and quality, pregnancy status, and whether the individual is actively breeding.…”

“…Both females and males excrete more GCMs during reproductive seasons than non-reproductive seasons, with differences in GCM levels between females and males occurring in some species. For example, female red foxes ( Vulpes vulpes ) had greater variation in peak GCMs than male foxes [ 22 ], while there were no differences in fecal GCM levels between female and male bat-eared foxes ( Otocyon megalotis ; [ 23 ]). Conversely, an individual’s sex and age influenced GCM levels in Mexican grey wolves ( Canus lupus baileyi ; [ 24 ]).…”

“…Collecting scats and the resulting analysis of fecal GCMs (fGCMs) have been conducted since the early 2000s and results in little to no physiological feedback [ 8 , 35 ]. Several studies have examined levels of fGCMs in carnivores [ 7 ], including coyotes [ 4 , 36 ], bat-eared foxes [ 23 ], and Mexican gray wolves [ 24 ]. Non-invasive fecal sampling was used to explore the causes of low reproduction in female red wolves [ 20 ].…”