Opossums, like other animals, obviously make various types of movements. Ordinarily one tends to keep within a relatively small area that is familiar to it and that satisfies all its ecological requirements. This constitutes its home range. Many other animals, including various mammals, are characterized by territoriality; individuals, pairs or groups occupy definite areas, defended as territories, to the exclusion of other members of their species. Like Lay (_loc. cit._) we found no evidence of territoriality in the opossum. In general, opossums are unsocial but not intolerant in their behavior. In the present study numerous individuals of both sexes and various sizes and ages were found to be occupying the same area simultaneously, with overlapping but no exact correspondence in home ranges. Occasionally two or more opossums may use the same den, but each goes its own way on its foraging and it seems that no sociability is involved. On many occasions opossums were tracked in soft snow or mud which retained footprints. Under conditions prevailing locally, it was difficult to follow such a trail for any great distance but trailing did divulge information concerning the type of route followed and the method of foraging. Opossums were found to have little inclination to follow beaten trails, either their own or those of other animals. A foraging opossum moved about in an extremely circuitous and erratic route, seldom taking more than a few steps without a change of direction, and frequently crossing its own course in a series of loops, some only a few feet or a few inches in diameter. In moving about, it is guided partly by the tactile and olfactory stimuli of objects on or beneath the ground surface which are potential food sources. Foraging consists of a succession of tests of such objects, as the animal moves from one to another. Opossums may habitually follow intermittent creeks or gullies or even roads when these provide better foraging than does the adjoining habitat. Metamorphosing amphibians may provide such a food source along a creek and the supply of crushed insects or other small animals along a road attracts the opossum. Food is found by turning chips and leaves, and by poking and probing in chinks and crevices with its snout and paws. On a few occasions short, well worn trails made by opossums were found, from dens to near-by feeding areas where grape tangles provided an abundant and readily available food source over periods of weeks. More often, an opossum follows no trail in its search for food, but seems to wander at random within its home range.