Risk assessment and avoidance in juvenile golden hamsters exposed to repeated stress

Abstract

Juvenile hamsters are typically less vulnerable to social subjugation than adults, although they will avoid aggressive individuals in some situations. The purpose of this study was to determine the extent to which social subjugation stimulates fear- or anxiety-like behavior in juvenile hamsters in both social and non-social contexts. Social context testing was conducted in a Y-maze while the non-social context apparatus consisted of an open field arena and a lat-maze. In the Y-maze, subjects were exposed to an unfamiliar aggressive adult hamster. Compared with non-subjugated controls, subjugated juveniles spent significantly more time in the area furthest from the aggressive adult stimulus. In addition, socially stressed animals were more likely to avoid the arm of the maze containing the social stimulus. When they did walk in the arm containing the social stimulus, subjugated individuals were more likely to ambulate slowly. Subjugated hamsters also performed fewer olfactory investigations in the proximity of the unfamiliar aggressive individual. Despite these behavioral differences detected between groups during testing in a social context, we observed no differences between groups in the open field and lat-maze. This suggests that the effects of subjugation observed in the Y-maze are specific to exposure to a social context and that social subjugation in juvenile hamsters does not result in a generalized state of fear. Instead, subjugated juveniles learned to avoid adult males and were otherwise behaviorally similar to non-subjugated controls.