Behaviour of the Eurasian otter at latrines along a gradient of anthropogenic landscape context

Abstract Increasing human pressure on fluvial ecosystems can alter wildlife behaviour, particularly where human activities modify habitat structure and the conditions under which behaviours are expressed at key communication sites. In this study, we examined how environmental and proxies of anthropogenic variables influence behavioural expression of the Eurasian otter Lutra lutra at latrine sites, which function as key locations for chemical communication. We analysed video recordings obtained from camera traps deployed at 13 latrines across seven rivers in northern and central Spain between 2022 and 2024. Using these recordings, we constructed an ethogram and quantified both the occurrence and the relative duration of observed behaviours. A total of 800 behavioural observations corresponding to 11 distinct behaviours were identified, with sniffing and faecal marking being the most frequent, confirming the communicative role of latrines. Most recordings involved solitary individuals, whereas observations of pairs or females with cubs were rare. Anthropogenic variables did not consistently explain behavioural occurrence but influenced the relative duration of several behaviours. Grooming and body rubbing decreased with proximity to human infrastructure, whereas time allocated to vigilance increased. Sniffing behaviour occupied a greater proportion of time during nighttime and in river sections with higher vegetation cover. Overall, these findings suggest that behavioural expression at Eurasian otter latrine sites does not substantially vary in terms of behavioural occurrence across the studied gradient of anthropogenic landscape context, although the time allocated to specific activities may be adjusted according to local conditions. Behavioural time allocation at communication sites may therefore represent an important mechanism allowing otters to maintain information exchange across human-modified landscapes while adjusting behavioural investment according to local environmental conditions.