You might associate snoring with a sense of well-being. It may be the ultimate sound of acceptance, of your attention and affection being valued and appreciated. Your cat may purr contentedly when you pet it, brush it, or give it a favorite treat. But there are other reasons why cats snore.
Cats snore at frequencies between 25 and 150 hertz (Hz). You can feel the cat’s purr. What exactly does this mean?
Hertz is a unit of measurement for sound waves, also known as frequency. One hertz corresponds to one cycle of sound waves per second. Low frequencies (0-500 Hertz) are vibrating sounds that can be felt and heard, like the low instruments in an orchestra.
Mid frequencies (500 to 2,000 Hz) are the broad band of human speech, 250 to 8,000 Hz. High frequencies (above 2,000 Hz) are the high instruments of an orchestra; think of clanging cymbals.
Certain frequencies that are too high or too low can be annoying, harmful, or even deadly to those within earshot. However, the reverse is also true. Numerous scientific studies have shown that the right frequencies relieve stress, reduce pain, and promote healing. Healing music and catcalls fall within this frequency range.
One landmark study, “Cat purrs: a healing mechanism? concluded that the vibration frequency of purring “promotes bone growth and soft tissue healing.” The study was first published in the New Zealand Veterinary Journal and later in the November 2001 issue of the Journal of the Acoustical Society of America. The study’s conclusions are often cited and are likely the reason why “purring” has become the most studied vocalization method in cats by scholars and researchers.
In a 2020 study, researchers led by the Korean Veterinary Medical Association examined 20 feline vocalizations, including purring. They titled their study “Feline Vocal Communication” and published their findings in the January 2020 issue of the Journal of Veterinary Medicine.
According to the researchers, kittens can learn to purr from their mothers as early as a few days of age. Purring is defined as “a low, continuous, rhythmic sound produced during breathing,” and kittens purr with their mouths closed during inhalation and exhalation, and their “respiratory rate accelerates when at rest.”
The growl may last less than a second or for several minutes and may be combined with other vocal sounds, but is generally low-pitched. The growl allows kittens and their mothers to communicate in close proximity without being heard or detected by predators. In other words, one must be in close proximity to the cat to hear or feel the vibrations and receive the message.
The researchers write “Purring has long been considered a sign of friendship and happiness in cats, but there are subtle variations in purring that can be used in different situations. Cats purr not only when they are “content and hungry, but also when they are stressed, in pain, or near death.”
Cats are very good imitators. For example, cats imitate birdsong and meowing imitates human communication. Although I have never heard it, several studies have mentioned “food-grabbing meows.” They purr higher than the average purr and mimic the cries of human babies to elicit human sympathy.
Since cats purr when they are in pain and purring is a healing frequency, some researchers have suggested that purring may be an attempt at self-healing. I have a snoring cat on my lap.
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Snoring and purring
In addition to the four feline species of the leopard genus, 34 of the 38 feline species snore. That means cheetahs, cougars, lynxes, bobcats, servals, and many other feline species snore. Four cat species that do not snore roar.
Snoring and roaring turn out to be mutually exclusive, which has to do with the anatomy of the vocal cords. The vocal cords of cats that snore have bones attached to them. The vocal cords of a snarling cat have no attached bones and have ligaments that stretch as air passes through the vocal cords, resulting in a louder, lower sound, and in larger cats, larger vocal cords.
Leopard lizards that roar without purring include