Wolves begin mating when they are 2 to 3 years old, sometimes establishing lifelong mates.
Wolves usually rear their pups in dens for the first six weeks.
Dens are often used year after year, but wolves may also dig new dens or use some other type of shelter, such as a cave. An average of five pups are born in early spring and are cared for by the entire pack. They depend on their mother's milk for the first month, then they are gradually weaned and fed regurgitated meat brought by other pack members. By 7 to 8 months of age, when they are almost fully grown, the pups begin traveling with the adults. Often, after 1 or 2 years of age, a young wolf leaves and tries to find a mate and form its own pack.