A hierarchy of dominant and subordinate animals within the pack helps it to function as a unit. Wolves communicate with fellow pack-mates and other wolf packs by scent marking, vocalizations, facial and body postures. Also use barks, whimpers, growls and howls to express themselves. Pups begin to howl at one month old. Wolves mate in February or March.
Females give birth two months later to a litter of pups.
An average litter is four to seven pups. Litter size and pup mortality depends on food supply, weather and the health of the mother. Wolves need open land and an abundant supply of prey to survive. The illegal killing of wolves is a serious problem, especially for small populations. Almost one-quarter of the wolves in Minnesota are illegally killed each year.