Music that incorporates everything from purrs to meow-like sounds is gaining feline fans, according to a new study that suggests cats enjoy tunes that are crafted just for them.
The study, which has been accepted for publication in the journal Applied Animal Behavioral Science, adds to the growing body of evidence that many animals respond favorably to species-specific music. This is music that takes into account a particular animal's favorite sounds, hearing range, commonly used tones and other factors.
"Here we found that cats showed orientation and approach behavior toward the speaker with the cat music, often rubbing against the speaker while the music was on," lead author Charles Snowdon of the University of Wisconsin, Madison, told Discovery News.
Snowdon and colleague Megan Savage worked with composer and musician David Teie, who created the cat-centric music.
"We looked at the natural vocalizations of cats and matched our music to the same frequency range, which is about an octave or more higher than human voices," Snowdon said. "We incorporated tempos that we thought cats would find interesting -- the tempo of purring in one piece and the tempo of suckling in another -- and since cats use lots of sliding frequencies in their calls, the cat music had many more sliding notes than the human music."
The researchers then played this music for 47 domestic cats in their homes with their owners present. As a comparison, Snowdon and his colleagues also played "human" music for the cats. This consisted of two pieces that have been highly rated as being "pleasing and affiliative to humans": Gabriel Fauré's Elegie and Johann Sebastian Bach's Air on a G String.
While the relaxing classical music did not freak out the felines, they basically ignored it, showing no interest whatsoever. The special "cat music," however, grabbed their attention and led to head-rubbing against the speaker.
Cats possess scent glands along their tails, on each side of their head, between their front paws and on other parts of their body. When a cat rubs something or someone, prior research concludes this means the cat is claiming that thing or individual. In this case, the cats appeared to be trying to claim the music, represented by the speaker playing it. They did not rub against the speakers when the Bach and Fauré pieces were played.
Most of the cats in the study were mixed breeds, so the researchers could not determine if certain breeds like music more than others. They did, however, discover that younger and older cats respond more to feline-specific music than middle-aged cats.
The "music for cats" project isn't just a novelty, as the researchers "think this work could benefit shelter cats," and particularly those that are accustomed to human companionship.
"We think of cats as highly independent of their human servants, but there is some research showing that cats experience separation anxiety, which is greater in human-raised cats than in feral cats," Snowdon explained.
Other researchers are studying whether or not species-specific music is pleasing to zoo animals. So far, it appears that some species -- and some individuals -- like music more than others. One goal might be to give the animals direct control over when to listen to and for how long, allowing animals to control their own music the way people do.
Kazutaka Shinozuka and colleagues at Keio University have also studied regular music's effect on animals. So far, most seem to prefer classical pieces.
"Generally speaking, modern music includes much dissonance," Shinozuka said, explaining that dissonance doesn't seem to be pleasing to non-human species.
There is one surprising exception, however. In an earlier study, Teie played a variety of tunes for cotton-top tamarins. The diminutive, fluffy monkeys seemed to calm down whenever they heard the heavy metal band Metallica.