International Journal of Comparative Psychology

Twenty seven experimentally naïve adult female rats were exposed to a novel arena with shelters for a period of 15 min. Various measures of their pelage-cleaning behavior were analyzed. Bouts of grooming were shown to increase in duration and complexity and decrease in their rostral content over the span of the measurement period. Simultaneously, decrease in risk-assessment activity, as measured by the stretched attend posture, was noted in association with consecutive bouts. The effect on risk assessment appears to demonstrate that the aforementioned changes in grooming bout parameters resulted from a decrease in the level of stress. Differences in the characteristics of the early and the late grooming bouts suggest that bout initiation and bout continuation are affected by two relatively independent mechanisms involved in the shaping of pelage-cleaning behavior.