Large territories are found where prey is less common, or where prey may migrate. The boundaries of such territories can be difficult to define, and some wolf packs of Canada's Northwest territories do not seem to have fixed territories during the winter, a time during which the wolves must travel long distances to follow migrating caribou herds. Other factors that may influence the size of a territory that a pack will defend include climate, the presense of other wolf packs and the nature of the terrain. In areas where there is little suitable wolf habitat and a high density of people, wolves often have rather small territories. Wolves tend to have larger territories in areas where there are many other large predators, such as wild cats and bears, present.
Wolves use many methods to define their territories.
In territories that are well defined, the most important method wolves use to mark out their territory is scent marking . Wolves use urine to mark out their territory, and wolves can differentiate the odour of their packmate's urine from a foreign wolf's urine. Wolves have excellent senses of smell, and when a pack ventures onto a territory that has been marked by other wolves, the pack will either leave or risk a fight. The alpha female usually marks on a scent post that her mate has just marked, although during breeding season, the female may urinate first on the ground. All other females in the pack, as well as low ranking males and young wolves, will squat when they urinate.