Here is a science news story reported on-line.
Some parents neglect or physically harm their young.
Their abuse of helpless offspring mirrors the practices of other adults in their families, reflects hostile or emotionally ambivalent parenting styles, and intensifies in response to various types of social stress. Evidence of links between maltreatment of their young among monkeys and people suggests that nonhuman primates hold great promise as models for investigating this poorly understood behavior, say two psychologists who study monkey families. Their review of research in this area appears in the May Psychological Bulletin. These conservative estimates roughly match neglect and abuse rates in human populations, they say. In group-living monkeys such as macaques and mangabeys, neglect and abuse rarely occur together and may represent separate phenomena, Maestripieri and Carroll argue.