Designed as a model of mild adolescent stress relying on social instability, Chronic Social Stress (CSS) has been shown to modulate social interactions, hypothalamic-pituitary-adrenal function, and response to new stressors. The effects of CSS during both the juvenile and adult stages were assessed in male rats. CSS effects on play behavior, locomotor activity in an open field, and fearful behavior prompted by a predatory odor were examined. CSS was shown to have no effect on both juvenile social play behavior or on activity in an open field. CSS was shown to affect exposure to cat odor by reducing the number of entries in and out of a hide box and increasing risk assessment. These data suggest that CSS affects behavior related to the innate fear response in adult rats by either reducing the severity of exposure to cat odor or increasing coping mechanisms associated with stressful events.