An investigation of individual, age and sexual differences in the play of Rattus norvegicus (Mammalia: Rodentia)

Eight litters of Rattus norvegicus of the PVG/C hooded strain were observed in order to investigate the roles of individuality, sexuality and age in playful behaviour. Three measures of social play, namely, initiations, numbers of play bouts and numbers of playful elements performed were all found to be positively correlated. The incidence of social and solitary play were also positively correlated so that a concept of “playfulness” appeared to...