Maternal Style and Offspring Behavior in Macaca tonkeana

Maternal style can shape offspring behavioral profiles both in the early months and later in life. In nonhuman primates, mothering style can be described by three main dimensions: protectiveness, rejection, and warmth. Although many studies have been performed on this topic in Cercopithecines, we still know little about the more socially tolerant species of this subfamily. We aimed to determine the behavioral dimensions of maternal style in captive Macaca tonkeana, a species characterized by a particularly relaxed type of offspring rearing. We therefore investigated how mothering style influences offspring behavior at different developmental stages by observing the interactions of 30 offspring during the first 5 months of infant life and for 10 days when infants were 12 months old. We used principal component analysis to first extract the components from the variables describing the main interactions of mothers with infants and then the components from the variables describing the main interactions between offspring and their partners. We used linear and generalized mixed models to test the effects of maternal factors on offspring behavior. Our results showed that maternal style in Macaca tonkeana was described by two independent behavioral dimensions, which we labeled protectiveness and warmth. Maternal rejection was almost nonexistent in our captive groups. We did not find any relationship between maternal style components and infant behavior during the first 5 months of life. At 1 year of age, offspring reared by higher-warmth mothers showed greater sociability. Our findings are reminiscent of the dynamic properties of human parenting, corroborating the usefulness of comparative studies on parent–infant attachment.