Previous studies have shown that different social experiences, such as the interaction involving partners of different ages or among individuals of different sexes, significantly alter the play rate. In the present study, two experiments are described, the hamster being used as subject, to investigate the effects of litter size and to analyse the play fighting behavior among males. It was found that there was no significant difference in the time spent in play fighting by an animal when it was placed in groups of 2, 4 or 6 individuals (Exp. 1). Moreover, the majority of animals did not show preferences during play fighting when they were placed in groups formed by four males (Exp. 2). Through these data it has been noted that the hamster distributes the total time spent in play fighting among the available partners. This fact can be explained by the hamster's social organization, because it is a solitary animal, which does not develop a clear and durable interaction with its playmates. Also, through other results, a certain stability was found in most of the behavioral categories registered such that they were not significantly affected by the manipulated variables.