The development of infant play in a captive group of lowland gorillas (Gorilla gorilla gorilla)

Abstract
Three infant gorillas born at the Yerkes Regional Primate Research Center of Emory University were studied during their first year and one‐half of life for various aspects of behavior, including solitary and social play, using both focal animal and one‐zero sampling. The appearance of play in these infants followed a developmental trend, beginning with mother‐infant play, and followed by solitary play, and then social play among peers. Mothers were initially very vigilant, repeatedly interrupting infant peer play bouts, this relaxing toward the end of the first year. Evidence for a possible sex difference in active social play is presented.