Ole-Gunnar Støen, Jonas Kindberg, Anne Hertel, Rick Heeres

Research over the past two decades has shown social–spatial structuring among female Scandinavian brown bears, suggesting an awareness of conspecifics across the landscape. This is notable because brown bears are regarded as solitary, raising questions about how social contact occurs when close associations are not a consequence of aggregation. We build on this work by identifying drivers of female–female encounters using 16 years of high-resolution GPS data.
We constructed a matrix of adult females occurring within 1000 m of one another and defined encounters as dyads entering a shared space within 100 m at the same time. We modeled how relatedness, age, body size, reproductive status, season, diel period, bear density, home range size, and home range overlap influence the distances females maintain and the probability of encountering one another. We included dyad identity as a random effect to account for repeated observations of the same female pairs.
We found that encounters are strongly structured by social and life-history traits rather than arising solely from shared space use. Closely related females maintained shorter distances and had higher encounter probabilities, whereas older females were more spatially separated and less likely to encounter conspecifics. While larger home ranges and spatial overlap increased encounter probability, encounters were not explained by space use alone. Reproductive status and season further shaped encounter dynamics, with pronounced seasonal increases during pre-mating and mating periods.
Importantly, mother–daughter pairs exhibited distinct and flexible relationships, with distances and encounter probabilities varying by reproductive status and season. Dyad-level differences suggest pair-specific tendencies in how females share space. Together, these results demonstrate that female brown bear encounters reflect dynamic, context-dependent behavior, highlighting previously unrecognized complexity in social behavior.