Exploratory behaviour of rats at oestrus.

Twenty-seven nulliparous RHA/Verh female rats received a daily-6-min test in a familial maze. The complex maze was of the Dashiell type and included a small illuminated central arena. It was demonstrated that these female rats more rapidly patrolled the maze at oestrus than on either of the two days preceding or following oestrus. Consistent with a number of earlier reports, it was also shown that general locomotor activity increased, body weight decreased, and the frequency of entry into the illuminated maze centre increased at oestrus.