Why Cats Purr
Everyone knows that cats purr, but do you know how and why cats purr? Interestingly enough, it has been found that the frequency of a cat’s purr is in the range of healing, as understood by the Schumann resonances, and is very therapeutic to both the cat and it’s humans.
According to an 18 March 2001 article by David Harrison in the London Telegraph: “… the purring of cats is a natural healing mechanism“. Ranges between 27 and 44 hertz are the dominant frequencies for a house cat, and 20-50Hz for the puma, ocelot, serval, cheetah and caracal.
The answer to why cats purr seems obvious enough, doesn’t it? A purring cat is a contented cat, yes? This surely must be true – but it is not. Repeated observation has revealed that sick cats in great pain, injured, in labor and even dying – often purr loud and long. Now, these can hardly be called contented cats.
It is true, of course, that contented cats do also purr, but contentment is by no means the sole condition for purring. A more precise explanation, which fits all cases, is that purring signals a friendly social mood, and it can be given as a signal to, say, a vet from an injured cat indicating the need for friendship, or as a signal to an owner, saying thank you for friendship given.
The First Purring
Purring first occurs when kittens are only a week old and its primary use is when they are being suckled by their mother. It acts then as a signal to her that all is well and that the milk supply is successfully reaching its destination. She can lie there, listening to the grateful purrs, and know without looking up that nothing has gone amiss. She in turn purrs to her kittens as they feed, telling them that she too is in a relaxed, co-operative mood.
The use of purring among adult cats (and between adult cats and humans) is almost certainly secondary and is derived from this primal parent-offspring context.
Do Wild Cats Purr?
An important distinction between small cats such as domestic species and the big cats, such as lions and tigers, is that the latter cannot purr properly. The tiger will greet you with a friendly ‘one-way purr’…a sort of juddering splutter…but it cannot produce the two-way purr of the domestic cat, which makes its whirring noise not only with each outward breath (like a tiger) but also with each inward breath.
The exhalation/inhalation rhythm of feline purring can be performed with the mouth firmly shut and may be continued for hours on end. In this respect small cats are one up on their giant relatives, but big cats have another feature which compensates for it. They can roar, which is something small cats can never do.
This article on why cats purr by Dr. Rick Marrinson: Purring seems to be caused by the cat’s vocal chords being drawn together and apart so quickly that it creates a vibration in the larynx or voice box.
This vibration is strong enough to be transferred throughout the cat’s body. Other mammals, including humans, don’t have the muscles to move the vocal chords that quickly.
Why Do Cats Purr?
We suspect that purring is a form of communication. It is thought that the original function of purring was to enable a kitten to tell his mother that “all is well.” This first occurs during nursing. A kitten can’t meow and nurse at the same time, but it can purr and nurse without any problem. The mother often purrs back to reassure the kitten.
Older cats may purr when they play or approach other cats, signaling they are friendly and want to come closer. Cats also purr when they are contented, such as when they are petted, again giving the signal “all is well.”
Are These The Only Times Cats Purr?
Strangely enough, cats can also purr when they are distressed. Sick and injured cats, and those in veterinary offices often purr. This is rarely because the cat is happy to see me! It is thought that this is the cat’s way of reassuring and calming itself.
When a cat is purring, it’s almost impossible to hear its heart or lungs very well. Many cats will stop purring if they see running water from a faucet. So, don’t be confused if you see your veterinarian turn on the faucet in the exam room in an attempt to stop the purring so your cat can receive a more thorough exam.
Are cats the only animals that purr?
Cheetahs and ocelots are two other feline species that make a purr-like sound. But I have personally seen one other another animal attempt to purr. This was a small dog that, only while being petted, emitted a rhythmic low-pitched growl.
As it turns out, this dog had been orphaned as a puppy but nursed from a cat that had recently had kittens. This dog was mimicking the purring sound as best it could and even used is at appropriate times.
So in light of the above, when you have a sore tummy, a good idea would be to get your kitty, lay her on your lap and enjoy some together time, while her purring helps to sooth your pain!