Howling

In canines

The long-distance howling of wolves and coyotes is one way in which canines communicate. Long-distance contact calls are common in Canidae, typically in the form of either barks (termed "pulse trains") or howls (termed "long acoustic streams").

Wolves howl to assemble the pack usually before and after hunts, to pass on an alarm particularly at a den site, to locate each other during a storm, while crossing unfamiliar territory, and to communicate across great distances. Under certain conditions, wolf howls can be heard over areas of up to 130 km² (50 sq mi). The phases of the moon have no effect on wolf vocalization, and despite popular belief, wolves do not howl at the moon.

Wolf howls are generally indistinguishable from those of large dogs. Male wolves give voice through an octave, passing to a deep bass with a stress on "O", while females produce a modulated nasal baritone with stress on "U". Pups almost never howl, while yearling wolves produce howls ending in a series of dog-like yelps.

Howling consists of a fundamental frequency that may lie between 150 and 780 Hz, and consists of up to 12 harmonically related overtones. The pitch usually remains constant or varies smoothly and may change direction as many as four or five times. Howls used for calling pack mates to a kill are long, smooth sounds similar to the beginning of the cry of a great horned owl. When pursuing prey, they emit a higher pitched howl, vibrating on two notes. When closing in on their prey, they emit a combination of a short bark and a howl. When howling together, wolves harmonize rather than chorus on the same note, thus creating the illusion of there being more wolves than there actually are. Lone wolves typically avoid howling in areas where other packs are present. Wolves from different geographic locations may howl in different fashions: the howls of European wolves are much more protracted and melodious than those of North American wolves, whose howls are louder and have a stronger emphasis on the first syllable.

One variation of the howl is accompanied by a high pitched whine, which precedes a lunging attack. Scent marking is more effective at advertising territory than howling and is often used in combination with scratch marks.

The howling of wolves and coyotes is similar, prompting early European explorers of the Americas to confuse the animals. One record from 1750 in Kaskaskia, Illinois, written by a local priest, noted that the "wolves" encountered there were smaller and less daring than European wolves. Another account from the early 1800s in Edwards County mentioned wolves howling at night, though these were likely coyotes.

In coyotes, "bark howls" may serve as both long-distance threat vocalizations and alarm calls. The sound known as 'wow-oo-wow' has been described as a "greeting song". The group yip howl is emitted when two or more pack members reunite and may be the final act of a complex greeting ceremony. Contact calls include lone howls and group howls, as well as the previously mentioned group yip howls. The lone howl is the most iconic sound of the coyote and may serve the purpose of announcing the presence of a lone individual separated from its pack. Group howls are used as both substitute group yip howls and as responses to either lone howls, group howls, or group yip howls.

Dog communication includes specific types of howls that have been identified in dogs, including:

• Yip-howl – lonely, in need of companionship.
• Howling – indicates the dog is present, or indicating that this is its territory.
• Bark-howl, 2–3 barks followed by a mournful howl – dog is relatively isolated, locked away with no companionship, calling for company or a response from another dog.
• Baying – can be heard during tracking to call pack-mates to the quarry.

The vocal repertoire of the fox, though substantial, includes fewer howling behaviors. At the age of about one month, fox kits can emit a high-pitched howl as an explosive call intended to be threatening to intruders or other cubs.