The effects of social deprivation schedules and days of testing on the play-fighting of juvenile golden hamsters were investigated. In Experiment 1, subjects totally (individually housed) or partially isolated (individually housed, but separated by a wire mesh 2 cm from another animal) for a period of 48 h spent significantly increased peer-peer bodily contact, play fighting, and play-fighting relative time (% of bodily contact time spent in play fighting), but exhibited decreased locomotor activity on the 1st day of testing. In Experiment 2, subjects reared since the 10th postnatal day with their mothers alone (chronically deprived of peer-peer social interactions) exhibited similar performances, except that locomotor activity was not affected. All dyads exhibited increased pinning turbulence (number of pinnings divided by time spent in play fighting) on the 1st day of testing, and the interactions between variables (deprivation schedules and days of testing) were statistically significant in most cases, suggesting that unfamiliarity between interactors also affect the performances of animals. We conclude that golden hamsters are sensitive to social deprivation, mothers do not substitute peer companions, animals reared in single-infant litters basically behave like socially-isolated animals, and the effects of induced social deprivation are reversible and disappear on days following testing.