Aggressive behaviour of the eight-year-old nulliparous isolate female monkey

Abstract

The infant-directed and age-mate-directed behaviours of four 8-year-old feral females and four 8-year-old isolate females were observed when paired in confined quarters with infant and age-mate stimulus animals. Although the isolates redirected a smaller proportion of their hostility away from the infant than did the ferals, they were not abnormally aggressive toward the infants and were certainly much less hostile towards infants than were 4-year-old nulliparous female isolates described in previous studies. On the other hand, the isolate females of the present report directed much more physical aggression toward the age-mate stimulus animals than did the ferals. As the nulliparous isolate female matures, she apparently becomes less aggressive toward infants and, if anything, more aggressive toward age-mates.