1. Why do cats purr?
Although many people think cats purr mainly when they’re happy or soothing their kittens, any veterinary professional or long-time cat owner will tell you that sometimes cats purr when they are sick or injured. So, is purring just used to express affection, or to comfort the weak or stressed?
It turns out to be both, but also something more. Studies have shown that cats’ purrs resonate at frequencies that promote healing of muscles and bones. This explains why cats heal faster and tend to have less bone and muscle abnormalities than dogs. (The later domestication of cats and less selective breeding may certainly be a factor, as well.)
In addition, a recent study showed that cats have developed a particular purr, called a “solicitation purr,” which they use to get humans’ attention. This is like a purr with a bit of a cry added to it, and many cat people will tell you that they hear this more urgent purr frequently in the morning when the cat wants to be fed.
Armed with these studies, I asked some cats I know why they purr, and if these studies are valid to them.
Of course the first cat I asked was my mentor and advice columnist, Maya:
“I’m glad someone is trying to figure it out, although if they just asked cats, they could find out a lot sooner! Purring, for me, is meditational. It’s both voluntary and subconscious, at times. I purr when I am feeling good, or when I want to feel good. I also purr when someone near me, like one of my people, needs some help feeling good. I can even send it long-distance, if I think about who needs it – you don’t have to hear it to get the vibration, the energy. Think about when you humans use your voice to hum to yourselves, to sing to another, or to make the Om sound in meditation. It’s a way you use frequency to raise your energy, concentrate and feel better. This is our way of doing that, although it does work a bit deeper, for us.
And yes, it is a special vibration. It heals both the body and the spirit. Why do you think many cats lie and purr on their sick people or animal friends? It’s a special talent we have, and it’s a fabulous part of being a cat!”
When asked about the solicitation cry, she answered, rather drily, “I have no idea what you’re talking about.” Nice try, kitty cat, very funny.
A kitten I asked answered:
“Purring is very important to me. I remember my mommy doing it to me. I do it to my person or the other cats to ask them to be nice to me. I also do it to make myself feel better. It feels really good to purr. I think all of those things you mentioned are good reasons why I purr, but also just because it is a part of me to do it.”
Other responses included:
• A very caring cat who wanted to ask his person if his purr made her feel better because he really wanted to help. He acknowledged solicitation purring, although he was afraid he’d be thought naughty for doing it, does get him what he wants.
• A very scientific-minded cat who found the studies fascinating and wanted to commend the scientists on their efforts, although he added “there is still much to be learned about our purrs by humans, and it’s something most cats can’t or won’t explain to you!” And…
• A proud young cat who just wanted to take the opportunity of our talk to show off what a “really nice, rumble-y” purr he has.
2. How do cats purr?
Scientists note that purring is unusual in that it occurs both during exhalation and inhalation, and it’s not something that can be explained just by looking at the anatomy of the cat. Many theories as to how purring is generated have been put forth and discarded, including cats having a special “purring organ,” cats using the hyoid apparatus (small bones found between the skull and the larynx), or even the vibration of the vena cava (a major vein) by the rushing of blood.
More recent studies have led scientists to believe that a nervous signal in the brain of the cat stimulates a very fast vibration of the vocal cords and/or “false” vocal cords (a pair of membrane folds behind the vocal cords). This vibration is thought by some to be coordinated with a vibration in the diaphragm (the muscle that regulates breathing), but it is not known if this is true or, if so, how this is coordinated.
Time to ask the cats!
“You humans. Always trying to explain away the magic! All I will say is, I create the physical aspect of purring – or it creates itself – between my throat and my tummy. The real creation of it is spiritual and mental. And even if you can’t purr like we can, you can feel the purr energy yourselves, in other ways. Think about that for a while!”
My scientific-minded cat friend acknowledged:
“I think that [theory]’s very good. I do generate it with my vocal apparatus, and also my lower breathing mechanism. It also resonates all through my head and body. However, the exact chemical foundation of this reaction, I cannot say. Perhaps it’s something they should study more, or it could be one of those mysteries that divide your theories of evolution or divine intervention. I can tell you, it sure feels mysterious!”
Other reactions included several cats who said they didn’t know exactly how they did it, some who’d never thought about it before, but thought the vocal cord/diaphragm idea sounded reasonable once they tried out their own purrs, and a few more who acknowledged that the coordinated use of their breathing muscles and vocal cords seemed pretty close to what they do, although perhaps a bit simplified. Most of those asked, however, were encouraging to humans who are trying to find out more about cats and their purrs. “I appreciate them trying to get to know us better,” one said, “it shows that they are trying to expand their knowledge and they care about us. I, for one, am happy to purr to try to make them feel better anytime!”
Want to read more about the studies on cat’s purrs? Check out
Why and how do cats purr? from the Library of Congress
Why do cats purr? and Cats Use Special Purr to Manipulate Humans from Scientific American
The Felid Purr: A bio-mechanical healing mechanism from the Fauna Communications Research Institute.