Further research around classical music found that songs heavily featuring violin aren't ideal, likely due to the instrument's high frequency, which dogs' "auditory profile" is more sensitive to. Evans pointed out that music ranging from 80 to 100 beats per minute seems to be a hit with pooches, including songs like Justin Bieber's "Sorry" and Shakira's "Hips Don't Lie." Evans has a theory as to why this is the case. "There's data from humans, particularly babies: if you play them repetitive sounds that match the frequency of the human heart beat, [the sound] relaxes them," Evans said. "It could be the same thing for dogs."
A question for music-loving dog owners is if it's possible to pinpoint their companion's favorite type of music. Evans has a few tips for figuring this out, with an eye toward what musical features dogs prefer. "If music has a ten-second repeat in it, it can have a very calming effect," Evans said. "Think about things like yoga chants where there is a repeating pattern to it: that's what we mean." Since your dog can't tell you in so many words, look for subtle signs they seem relaxed to clue you into whether they're digging your selection. Evans said there's less barking and a lot less movement in dogs who are enjoying music. Look for them to spend "more time lying in their bed," he said. "They're more chill."