"Wolf Conservation Center's education and outreach programs draw over fifteen thousand visitors a year, says director Maggie Howell. Their live webcams have a devoted audience. 'Unbeknownst to the wolves, they have a huge, global fan base,' Maggie explains. 'The wolves are creeping into our homes via these web cams.' Some of WCC's most popular on-the-ground events are 'Howl for Pups of All Ages' and 'Howl for Adults,' where people can blend their voices with wolves. WCC founder Helene Grimaud has spent years listening to wolves.

" 'Why do wolves answer our human howls?' I ask Grimaud now.

" 'Perhaps wolves are generously nondiscriminating,' Grimaud says wryly, then adds, 'One of the things that makes working with any wild animal so interesting and humbling is that you have to interact with them on their terms. Often they are quite forgiving of our bumbling attempts to connect in a proper and dignified way, in wolf terms. It could just be that the wolves interpret humans howling as an invasive threat from another pack. So the wolves want to advertise that this territory is already occupied.'

"In the same way that wolves mark territory by scent, they also set sound barriers that other wolves trespass at their own peril. It's intriguing to imagine what an acoustic map of wolf country would sound like – growls, guttural bluffs and rubato boasts, fortissimo barks, possessive, snarling arpeggios, a mournful undertone like a walking bass. Sometimes the sound map would rise to the sonorous pulse and operatic range of howling wolves. Do wolves ever just sing to make complicated music, as we do?

" 'One of the most intriguing elements of wolf howling is what scientists call social glue,' explains Grimaud. 'This spreading of good feeling like humans singing around a campfire, feeling closer to one another – it's that same idea: you howl or harmonize and so reaffirm your social bonds with one another. That's not surprising. Any pack animal really depends upon the other to survive.'

"Certainly humans are social pack animals. We are also profoundly moved by music, especially by making music together. That's why the word 'harmony' relates both to music and to relations between people, groups, even colors. When we hear human music, we physically attune to that vibration; when we sing together, we blend our voices, matching thirds and fifths and sometimes deliberate, clashing dissonance. We try to fit and find our part in the greater chorus.

"Wolves actually harmonize their voices with ours. 'Have you noticed,' Grimaud asks, 'that when a human – who is less naturally gifted in that wolf language – joins in a howl and his pitch lands on the same note, the wolves will alter their pitch to prolong the harmonization? It's very interesting. If you end up on the same pitch as a wolf, he will scale up or down, modulating his voice with yours.'

"If you listen to wolves singing, you'll hear that wolves rarely howl alone for long before the whole chorus is cued. That chorus is not just about harmonizing; it's also about survival. There's a phenomenon called the Beau Geste effect, in which howling together makes it impossible to identify a single wolf's voice or how many wolves are in concert. Even a family of two wolves can raise a mighty chorus to disguise their small size and create the illusion of a larger group's voice. In declaring their acoustic territory, the wolf chorus can travel long distances, giving the group the expansive space it needs to survive and thrive."