Sequences of feeding, sampling and exploration by wild and laboratory rats

Adult male wild rats and male laboratory rats, all Rattus norvegicus, were kept alone for 11 d is a residential maze. The maze had a central nest box and four arms radiating from it. Movement in the arms was automatically recorded. Three foods were supplied, one at the end of each of three arms; the fourth arm was empty. One food was usually much preferred to the othe two. Except on Days 1-3, access to the arms was for only 3h daily. The rate of visiting the arms declined during the first 3 d. The wild rats were more 'active' than the domestic in that they made more visits; but they spent less time in the arms. Visits were of two kinds: (a) short, usually < 1min; (b) long (> 4 min.: meals). The wild rats had shorter meals than the donestic. A 3-h period of access usually began with a bout of short visits to the arms. Each long visit to a food arm (a meal) was also typically followed by such a bout, sometimes after a period in the nest box (drinking). the first short visit after a meal by a wild rat was most often to the empty arm; but domestic rats distributed these visits evenly among the three arms in which they had not been feeding. In a given bout the second short visit by a wild rat, but not a domestic, tended to repeat the first. We interpret a bout of short visits as a patrol or re-exploration of the living space which may include sampling of all accessible foods. When a bout occured at the beginning of access to the maze arms, exploring was in 'competition' with eating; a bout after a meal may have represented 'disinhibition' of exploring.