Shared foraging grounds in a solitary rodent: evidence for mutual tolerance and kin-based spatial overlap?

Abstract Kinship is important for understanding the evolution of social behaviour in group living species. However, even solitary living individuals differentiate between kin and non-kin neighbours, which could lead to some form of cooperation, defined as both partners benefitting from each other. A simple form of cooperation is mutualism, where both partners benefit simultaneously. Here we tested whether there is mutual tolerance through sharing foraging grounds between kin in a solitary species. We used mini-GPS data loggers to investigate range overlap between kin- and non-kin neighbours in the solitary bush Karoo rat ( Otomys unisulcatus ). Next, we quantified the extent to which individuals shared foraging grounds containing food plants within their overlapping ranges. Lastly, using step selection functions applied to GPS fixes collected every five minutes, we analysed how individuals moved relative to each other. Kin-neighbours had larger home range overlap than non-kin neighbours (70% vs. 30%) and shared more of their foraging grounds (63% vs. 37%). Temporal analysis of spatial data showed no indication that neighbours avoided each other, independent of kinship. Instead, activity was synchronised. Overall, our findings indicate mutual tolerance between neighbours in relation to shared foraging grounds, with kin sharing nearly twice as much foraging space as non-kin. This mutual tolerance may facilitate spatial overlap among kin and could represent a precursor to more complex cooperative behaviour.