Wolves howl for many of the same reasons that other species use vocalizations: to warn others about predators, to defend their territories, and to find mates.1 Wolf pups begin howling as early as three to four weeks old, and as they get older, they learn to use their howls to coordinate with other pack members and determine what the group should be doing, and to locate young that get separated from their parents.

While wolves have been studied both in captivity and in the wild, scientists continue to learn about their communication and how hunting and habitat destruction by humans may be changing their behavior.3 For now, these are the known reasons why wolves howl.

 Defend Their Territory

Wolf howling between packs increases dramatically during mating season. When hormones are surging, wolves are more likely to show aggressive behavior towards members of other packs in order to defend their territory and the females in their pack. Wolves' average summer home ranges span 72 square miles, and territorial howling serves as a warning to outsiders to keep their distance.

They Miss Other Wolves

According to a study by scientists at the Wolf Science Centre in Austria, wolves tend to howl more if they are separated from another wolf that they have a close relationship with. In the past, scientists had hypothesized that wolves howled as a stress response to being separated from pack members. However, the European researchers found that levels of a stress hormone called cortisol did not significantly increase in pack members when a wolf was taken away from them. Instead, it seems that wolves howl when separated from another wolf simply to make contact with them and not because their absence is stressful. The higher the rank of the missing wolf, the more the rest of the pack howled.

To Communicate Their Location

Like many other species of animals, wolves use vocalizations to communicate. When wolves become separated, they will howl to locate the other members of their pack.4 Both individuals and entire packs may howl to find a missing member. The vocalization is also frequently used to locate missing pups or by adults to let the pups know that they are on their way home from foraging.4 Research on wolf behavior has looked into whether howling to communicate location is harmful to wolves that are in danger of being detected and hunted by humans, but so far no connection has been found.

Coordinate the Pack's Plan of Attack

Wolves normally hunt in packs, so it’s important that every member knows what they should be doing at all times during a hunt. Howling is one way to communicate plans and strategy during a hunting session so that no one is left behind and the hunt is successful. 

To Find a Mate

Eligible wolves must find a mate when the time is right. In the weeks leading up to the breeding season, single wolves will use howling to advertise that they are looking for a mate. By howling as an individual and not as part of the pack, a wolf can be recognized by others as available, attractive, and interested in breeding.5 Once wolves have paired, they will stay together until one of the members of the pair dies, at which point the surviving member will find a new mating partner.