Social organization of a solitary carnivore, the leopard, inferred from behavioural interactions at marking sites

Intraspecific interactions shape animal social networks and regulate population dynamics. Species with solitary life histories rely on communication cues for population regulation, especially olfaction for many terrestrial mammals. Increasing evidence shows complex social structures among presumably solitary species and although social factors may play a key role in spatial organization, we lack insights into how species with solitary life histories structure and maintain sociospatial systems. Herein, we applied a social network approach to decode leopard, Panthera pardus, behaviour and interactions at marking sites that we monitored with camera traps. We found that leopard social units within our study area consisted of up to five individuals and that same-sex and opposite-sex interactions were equally likely to occur. Individuals behaved and responded differently depending on the type of interaction, serving both territorial and reproductive purposes. Temporal segregation allowed intersexual co-occurrence, while same-sex co-occurrence may be facilitated through familiarity with stable neighbours. Central individuals interacted within and outside their social unit and appeared fundamental to group stability. The removal of these individuals, such as through legal harvest or pre-emptively as an attempt to minimize depredation, may weaken social cohesion and ultimately affect population demography. Our findings on intraspecific co-occurrence in a solitary carnivore depict a complex social structure that can be important for population stability and might occur in other solitary species.