The size of the territory of a wolf pack is determined by nutritional conditions and the density of wolves. In Finland the average size of an annual territory is 700–1000 square kilometres, depending on the used mathematical method. Wolves may move at any time of the day, but they are most active during dusk and at night. The wolf is a very fast mover that can cover vast distances with speed. Its hearing and sense of smell are excellent.
The wolf steers clear of people and you are very lucky to ever see one. The wolf has no natural predators.
The female wolves are in heat in February–March. During this time the alpha couple move near the rest of the pack by their twosome. After the female is no longer in heat, the couple chooses a place for a den and digs a cave into a sandy bank or other such location. The gestation period of a wolf is 60–63 days and the cubs are born sometime around the middle of May.
The birthing den can be a modest place. After three weeks, the cubs are moved to a better second den that is usually close to water. Wolves may use the same second dens year after year.
A female wolf typically gives birth to three to six cubs, but the wolf can have as many as ten cubs in one litter. The cubs are always guarded by one of the older wolves in the pack. This so-called babysitter can be a cub from the previous year's litter, for example. Cub mortality in wolves is high and nearly half of the cubs may die from parasites, diseases or lack of nutrition. The wolf's diet varies especially in the early summer. It might prey on moose as well as smaller animals, such as hares, rodents and birds. The cubs must be fed every day.
In the late summer the pack becomes significantly more mobile and its focus shifts away from the den. As autumn draws near and the cubs grow larger, hunting becomes easier and there are more large game animals such as moose calves to prey on. The entire pack participates in food acquisition and the young cubs learn how to hunt.