Mating
As breeding season approaches, members of the ®alpha¯ pair become increasingly friendly to each other. They sleep closer and closer together, and the male tends to stay close to the female as they travel. Both ®alphas¯ threaten competitors from within the pack with stares, ®growls¯, and grimaces. Meanwhile, male and female groom each other, place forepaws over the other's shoulders, and touch each other more and more.
Often, when about to copulate, individual mated pairs move out of the main pack for a few days. This is probably to avoid interference from other pack members. Sometimes pack associates try to get in on the mating, or they harass the mated pair during copulation.
Wolves copulate like ®dogs¯, the male mounting the female from behind. 
With the tense period of mating over, the pack animals' former affability and friendliness toward one another resumes. Now their attentions turn back to the task of selecting and preparing a den site for the pregnant ®alpha¯ female.
Female wolves have complex courtship, pair-bonding, and reproductive behavior as well as complex hormonal characteristics. They are capable of a reproductive state called "pseudopregnancy." Apparently, once a female matures sexually, she either becomes pregnant or pseudopregnant each year. During pseudopregnancy, the wolf's hormonal state is precisely the same as if the animal were pregnant even though she is not. This includes the ability to produce milk and possibly even to nurse the ®offspring¯ of another female. ®Dogs¯ also become pseudopregnant.
The period from conception to birth is about sixty-three days. During that time the pack will clean out an old traditional den or find a new location and help the alpha female dig a new one. Usually, the site will be higher than the surrounding ground, allowing the pack to watch over a large area. The site will also be near water, for the female will rarely travel far from her den after her ®pups¯ are born, at least until they are a couple months old.
The entrance to the den is usually quite small, allowing passage to only the pregnant female. The passageway may extend from a few feet deep to as far back as twenty feet. At the end will be a hollowed-out area barely larger than the tunnel itself. It is here the expectant mother will bear her young.
