Play and Testosterone in the Juvenile Male Yellow Baboon (Papio cynocephalus)

Abstract

Mammalian play is a behavior that has been of interest to researchers due to its social appeal as well as the confounding fact that it seems to be a wasteful and time-consuming action. Play is believed to serve as a practice arena for future dominance fights (Fagen 1974). The sexually dimorphic behavior (Pellis 2002; Loy & Loy 2005; Poirier & Smith 1974; Cheney 1978; Smith et al. 1998) sets the grounds for future antagonistic interactions. The interaction of testosterone and play as well as the predictive nature of play frequency was studied in a wild population of yellow baboons (Papio cynocephalus) that live in Amboseli, Kenya. Overall, play takes up a very small percentage of a wild yellow baboon, anywhere from .32 - 4.14 %, depending on age. Fecal testosterone was positively correlated with juvenile play percentage overall, but a yearly breakdown yielded only significant results for the second year of life. Interestingly, play rate during the second year of life predicted age of adult male rank acquisition, with more frequent players winning their first antagonistic interaction over an adult ranking male at a younger age. But play was not indicative of maturation age, and mother’s rank showed no affect on percentage of time individuals devoted to play.