They evolved as effective predators in part through pack formation. Usually only the alpha pair mate, beginning at about two years of age. Wolf litters, averaging six pups, are born in the spring. Pack ranking begins at birth, when the strongest pups push for position at their mother's teats. Since only about half may make it through the first year, the pups' survival is a top priority for each pack member.
Adults feed young pups with meat regurgitated from kills.
During territorial disputes, wolves may fight or even kill each other. In most cases, they simply avoid one another. A pack announces its presence by scent marking and howling. These behaviors are used to warn away strange wolves, to help pack members locate each other, and to express the relationships of dominance and dependence in the pack. Wolves disperse from packs for many reasons.