Abstract
14 male and 16 female Wistar (DAB) 113-day-old rats were observed in an open-field situation, in their home cages after manipulation, and in home cages without manipulation. Incidences of defecation and urination, locomotor activity, and digestive transit time were recorded during 4-min. sessions for 6 days. Animals were more likely to eliminate in the open-field situation than in their home cages, and more rats eliminated in this group than in the other two groups. It appears that the effect of the open-field situation on eliminative behavior is not related to that of manipulation incident to the observation of the animal in the open field. The decrease in digestive transit time of animals placed in the open field further suggests that the open-field situation is more effective than manipulation in modifying digestive transit time.