Preprint here on Bornean orang utan mums going out of their way, with higher travel costs, to overlap in shared areas with neighbour mums of similarly aged offspring.
'orangutan mothers incorporate their infants' social needs into daily ranging decisions, at a cost to their own energy budgets. This points toward an underappreciated form of maternal investment and illustrates how the social requirements of development can be met even near the solitary extreme of animal social organization.'

https://www.researchgate.net/publication/407488844_Maternal_ranging_strategies_facilitate_offspring_social_play_at_energetic_cost_in_the_most_solitary_ape