Infant Playing Behavior Of Three Primate Species In Captive

Data on playing behavior of infants were collected from three primate species in captive, including one group of assamese macaques (Macaca assamensis),one group of white-cheeked gibbons (Hylobates leucogeny) and two groups of fran?ois'langurs (Trachypithecus francoisi) in Nanning Zoo, Guangxi Province, between August 2008 and January 2009. We used focal animal sampling and all-occurrences recording technique to collect data. The main objective is to explore the possible functions and significance of playing behavior for the growth of primate infants.During the study period, A total of 2290 playing bout were collected in 528 15-min samplings (132 hours of observations) from assamese macaques, with 132 samplings for each individual. A toal of 2952 playing bouts were collected in 288 15-min samplings (72 hours of observations) from white-cheeked gibbons, with 48 samplings for each individual. A total of 473 playing bouts were collected in 1120 15-min samplings (280 hours of observations) from Fran?ois'langurs, with 112 samplings for each individal. Our results showed following:In assamese macaques, male infants spent significantly more time, exhibited significantly higher frequency in social playing (specially fight playing) than female infants, and showed more active than females as well. They preferred to play with other male infants of same age. These results support to the motor training hypothesis and social-relationship hypothesis. The patterns of playing changed with infant's age. Nonsocial play (special solitary locomotor play) declined significantly with infant age, while social playing increased. Moreover, infants showed more active in social playing.In white-cheekedgibbons, female infants spent significantly more time, exhibited significantly higher frequency in social playing (fight playing and embrace playing) than male infants, which is contrast to the prediction of the motor training hypothesis. There was no difference in nonsocial playing between male infants and female infants. There was significant in play-partner preference. Younger infants preferred to play with older infants, and middle-age infants preferred to play with same age and older infants, and older infants preferred to play with infants of nearly same age. This result generally supports the social-relationship hypothesis. The patterns of playing changed with infant's age. Fight playing and locomotor playing increased with infants age. Moreover, infants showed more active in playing.In francois'langurs, male infants spent significantly more time, exhibited significantly higher frequency in social playing (specially fight playing) than female infants, and showed more active than female infatns as well. But there was no differences in nonsocial playing between male infants and female infants. There was significant in play-partner preference. Younger infants preferred to play with older infants. Male infants preferred to play with male infants rather than with female infants. These results also support the motor training hypothesis and social-relationship hypothesis. The patterns of playing changed with infant's age. Nonsocial play (specially solitary locomotor play) declined significantly with infant'age, while social play increased significantly, but declined after 2 years old.