Supplementary material from "Conspecific density at marking sites influences the intensity and activity patterns of chemical and visual communication in brown bears"

Le résumé fourni par la source

Animal communication is a key component of animal ecology. In mammals, chemical signalling is the primary channel, though visual and acoustic cues also play important roles.While many studies have explored the seasonality and individual status associated with mammalian marking behaviours, little is known about how conspecific density shapes their occurrence, duration, and activity patterns. Here, we tested whether the intensity and temporal dynamics of marking behaviours are density dependent. Using camera traps, we monitored brown bear Ursus arctos marking behaviours (rubbing, pedal marking, and tree debarking) at 14 trees across nine mating seasons (2016)(2017)(2018)(2019)(2020)(2021)(2022)(2023)(2024) in the Cantabrian Mountains, northwestern Spain. Cameras operated continuously (24 h/day) for 122 monitoring days per tree per year, yielding 1,708 tree-days annually and a total of 15,372 tree-days. Our findings reveal that pedal marking, a male-exclusive behaviour, increased both in occurrence and duration with higher conspecific density, suggesting a densitydependent role in mate attraction and dominance signalling. Moreover, all different marking behaviours shifted toward more diurnality as the number of different bears increased. This indicates that bears may adjust their marking activity toward riskier daytime periods in human-modified landscapes. Overall, our study provides novel evidence that conspecific density can modulate the intensity and timing of communication behaviours.

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