Scroll through #SingingDog hashtags on social media, and you will find many clips of hounds howling along to their favourite tunes. But can a canine Callas show any real musicality?
That's the question that psychologist Aniruddh Patel at Tufts University in Massachusetts and his colleagues have attempted to answer with an ear-catching new study, which shows that some doggy divas really are perceiving pitch and adjusting their vocals accordingly.
The researchers were inspired by descriptions of wolves' howling in a pack. "Howling has some similarities to human singing, in that these are long, sustained vocalisation," says Patel. Observations from the wild suggest that each individual wolf attempts to hit a different tone. The result is a discordant chorus that might create the illusion of a much larger group, which would help to intimidate potential predators. "And so it had been theorised by some wolf biologists that they were actually paying attention and changing their pitch," he says.
This is very hard to test experimentally, of course, which is why Patel and his colleagues turned to house pets. They asked a handful of dog owners to record their hound's harmonies to their personally preferred track – first in the original key, and then in versions that had been transposed three semitones above and three semitones below – to see how they would respond to the change in pitch.
The researchers focused their analyses on two ancient breeds – Samoyeds and shiba inus – that are thought to be more closely related to their wolf ancestors than modern varieties. To increase the statistical reliability of the analysis, each dog had to produce at least 30 howls, lasting at least 1 second each, for each of the transposed versions.
All four of the Samoyeds studied showed some sensitivity to the track's pitch, consistently adapting their vocalisations to the new key, though in no cases did they match it exactly.
"They're trying to have some relationship to what they're hearing with their own voice; they're not just being triggered to unleash some instinctive and inflexible response," says Patel.
The two shiba inus, in contrast, appeared to be tone-deaf. "It's possible there's some genetic variation within ancient breeds, making some more predisposed to howling," Patel hypothesises – though he admits he might have found more musicality in a larger sample.
The findings might offer some insights into the origins of human music. Some theorists have argued that singing evolved from the fine motor control that comes with speech, which allows us to mimic complex sounds, but the fact that dogs can also control pitch without any other forms of vocal learning suggests that language would not have been a necessary precursor. "It's possible that our ability and desire to coordinate pitch with others when we sing has very ancient evolutionary roots, and may not just be a byproduct of our ability to imitate complex sounds," says Patel.