Beyond the Canopy: Social Play Behavior in Wild Spider Monkeys (Ateles geoffroyi)

Play is a multifunctional behavior that may confer different advantages depending on the context, the species, sex, and age of the players. Despite numerous studies of social play in primates, we know little about this behavior in platyrrhines. This study was designed to provide a systematic description of social play in a wild group of Geoffroy's spider monkeys (Ateles geoffroyi). We conducted behavioral observations of acrobatic social play, object social play, cuddling play, and rough-and-tumble play in a large group of spider monkeys (N = 54) in Yucatan, Mexico. Over 5 months, we recorded and analyzed 104 play sessions. The probability of engaging in social play was higher for infants and juveniles than for subadults and adults, and it did not differ between sexes. Moreover, the probability of engaging in different types of social play did not vary across individuals based on their sex and age, nor on the frequency of play faces. Play sessions lasted longer when both players were younger and with a higher number of players, but there was no significant variation in session length associated with the frequency of play faces or players' sex. Overall, our study revealed patterns of play behavior that suggest substantial flexibility in play in this species, in line with the high levels of tolerance that characterize spider monkeys.