The development of peer-mate relationships in Japanese macaque infants

The play behavior of Japanese macaque infants was studied for 6 months at Arashiyama, Japan. Three types of play were identified. The first (solitary play) was observed in five to 12-week old infants. The second type of play (parallel play) was observed in infants from 12 to 21 weeks old. After the 12th week, the third type of play (associate play) was seen. At this point the infants seldom played without partners. It is in associate play that dominant and submissive behavior may be seen, and from which dominance relations may be assumed. It is said that the rank of a 12 week-old infant parallels that of its mother.