OPEN-FIELD NIDUS AND PULLUS INDEXES IN MUS-MUSCULUS L

Swiss albino mice (Mus Musculus L.) were studied in an open field (OF) . The question whether laboratory rodents were more attracted to a nes t equipped with familiar odoriferous cues from the home-cage bedding o r to signals of an unfamiliar newborn pup inserted in the OF was addre ssed. The results of the three quantitatively recorded OF behaviors, a mbulation, retrieval and radial latency, indicated that in females bot h ambulation and retrieval were enhanced by the presence of a pup in a nestless field; in males locomotion was suppressed by a nest in a pup less OF. In the case of both sexes radial latency was determined by th e OF position of a nest. A comparison between the two qualitative asse ssments, the nidus and pullus indices, yielded that the sex of the adu lt and the OF positions of both targets equally impacted attraction to wards both nest and pup.