Encoded Information Within Urine Influences Behavioural Responses Among European Badgers (Meles meles)

Metabolic by-products like sex-steroid metabolites convey information regarding an individual’s physiological fitness and reproductive state. Urine and faeces containing these excreted metabolites can function as cues for conspecifics within social contexts, particularly for mate selection. Our pilot study investigated in scent provisioning experiments how donor- and responder-related characteristics influenced behavioural responses towards excreted sex-steroid metabolites. We used 51 urine samples with known urinary hormone concentrations (determined by EIA corrected for specific gravity) collected from known individuals in a high-density population of European badgers ( Meles meles ) in Wytham Woods, Oxfordshire, UK during the spring mating season. Samples were provided in Eppendorf tubes pushed into the ground near badger setts to assess how response likelihood, sniff duration, and countermarking responses varied according to donor-related traits (age, sex, group familiarity and hormone concentrations). From 143 videos containing 26 identifiable adult responders, we observed adult badgers modifying their behaviour towards urine samples based on the perceived relevance to their own traits with badgers investigating and countermarking urine from opposite-sex donors more often than urine from same-sex donors. This suggests that urine-marking can serve as an adaptive signal for individual advertisement. Additionally, all badgers were more likely to investigate male urine (containing testosterone) than female urine (containing oestradiol); however, no other clear effects of sex-steroid metabolites were noticed. We consider that this could be a feature of the social evolution of badgers or arise because badgers signal reproductive status through other olfactory secretions, notably their unique subcaudal gland marking behaviour.