Maternal aggression to its offspring in Japanese monkeys

Aggressive behaviors by mothers toward their offspring and the interactions related to them were observed for one year in six separately caged mother-offspring pairs of Japanese monkeys (Macaca fuscata). Maternal aggression showed changes both in quality and quantity in the course of the offspring's development, and it was caused mainly by behavior that the offspring directed toward the mother. It was interpreted that their actions increased irritability in the mother, and this interpretation, is supported by the fact that the offspring reacted to the mother's aggression by stopping these behaviors and/or, retreating from her. Maternal aggression functioned to promote the offspring's independence from its mother.