Parenting styles of abusive mothers in group-living rhesus macaques.

Maternal abuse of offspring in group-living monkeys was investigated to assess whether abuse of infants can be interpreted as an adaptive reduction of parental expenditure or as a behavioural pathology. I compared the parenting styles of 10 abusive and 10 non-abusive rhesus macaque, Macaca mulatta, mothers living in three large captive groups over the first 12 weeks of infant life. I also analysed the social interactions between mothers and infants and other individuals. Abusive females scored higher than controls on several measures of maternal protectiveness and rejection, indicating that they were highly controlling mothers. They also received fewer contacts and approaches from other individuals, and tended to be more aggressive and more interested in other females' infants compared to non-abusive mothers. Infant abuse was accompanied by similar or higher parental expenditure in the offspring rather than by a reduction in expenditure, as predicted by the adaptive hypothesis. Therefore, the results of this study support the hypothesis that infant abuse is a form of behavioural pathology. Infant abuse in rhesus macaques shows parallels with that in other primate species, but some of its characteristics could be a by-product of species-specific behavioural adaptations of rhesus macaques. Copyright 1998 The Association for the Study of Animal Behaviour.