Classical music isn't just for aristo-cats; homeless cats can benefit too.

 We use classical music to cover stressful noises like cleaning noises, people noises and dog noises, said Dilara Parry, the cat behavior and socialization coordinator for the San Francisco Society for the Prevention of Cruelty to Animals (SF-SPCA).

The SF-SPCA, one of the first no-kill animal shelters in the United States, keeps the radio tuned to the classical station as a white noise. The constant music helps cats adjust to their surroundings, shelter workers say.

Since we take in and work with many cats with behavior issues, and since many of them are former ferals or otherwise very frightened, we thought the music might help, said Nancy Guelzow, who works with problem cats in the SF-SPCAs Cat Behavior Department.

Choosing non-stressful music is essential to maintaining calm in the shelter.

We play classical [music] because it doesn't have a great deal of dissonance or percussion, Guelzow said. The volume is set at a medium level -- loud enough to drown out other shelter sounds, but not so loud as to be unpleasant to their ears.

Parry recommended avoiding music that imitates animal sounds. If I were going to give shelters advice, I'd say avoid noises that mimic cat meows, she said. Parry also cautioned against loud music because it may upset the cats.

Right now, I have the classical station on in the office, with two feral kittens on the way to socialization and an older adult who is not eating well -- they're all snoozing, Guelzow said.