Why Does Your Cat Purr?

Most of us assume that cats purr because they’re happy or contented. After all, when your cat contentedly curls up in your lap for some well-deserved scratches and rubs, she’s obviously one happy kitty.

However, cats also purr when they’re frightened or feel threatened, such as during a visit to the vet, or when they are stressed.  They also purr as a method of communication.

But not all cats can purr. Domestic cats, some wild cats and their relatives — civets, genets and mongooses — purr, and even hyenas, raccoons and guinea pigs can purr. However, cats that purr can’t roar, and cats that roar can’t purr because the structures surrounding roaring cats’ larynxes aren’t stiff enough to allow purring.

How Do They Do It?

A cat’s purr begins in its brain. A repetitive neural oscillator (rhythmic or repetitive neural activity in the central nervous system) sends messages to the laryngeal muscles (their larynx and diaphragm), causing them to twitch at a rate of 25 to 150 vibrations per second. This causes the vocal cords to separate when the cat inhales and exhales, producing a purr. Because the muscles work both during inhalation and exhalation, this gives the impression that they can purr continuously.  The air actually passes through the valve that opens and closes very rapidly which creates the purr sound.

When Do They Do It?

Cats purr in a variety of situations and in response to different stimuli. This is analogous to people and their laughter. What causes one cat to purr or one human to laugh may be completely different than what causes the same behavior in another.

Things that can stimulate feline purring include:

* Contentment: Sitting in a favorite human’s lap, lying in the sun, nuzzling up to a favored feline friend are all examples of situations that can induce purring. These are circumstances that seemingly represent true feline contentment.  Tiny kittens will purr and knead their moms while nursing, which is a sign of contentment. In older kittens and cats, contentment purring might occur while they are eating, being pet or lying in a warm, cozy spot. They’re purring with a feeling of security of safety.

* Communication/Wanting Attention: Purring can accompany feline requests for something they want, and might be heard at mealtime or when a kitty wants some lap time. This purring is often associated with some vocalization and animated behavior such as weaving in and out of their human’s legs.  You may find that your cat is certain to wake you up in the morning by jumping on the bed, kneading and purring. This purring is mostly likely just a way of getting your attention to alert you to the fact that it’s time to be fed.  Not surprisingly, cats seem to purr with greater urgency when hungry.

* Fear or Stress: Believe it or not, some cats purr when distressed or fearful. Such purring is commonly observed in a veterinary hospital setting, and can be quite audible.  Purring may have a calming effect on your cat, which is why they may do it when they’re afraid. Visiting the vet or being in a strange environment might cause a cat to begin purring because she is stressed or anxious. In that case, purring would be akin to how humans soothe themselves by crying, laughing, distracting themselves, or even organizing their desk.

* Kitten-mother connection: Kittens begin purring when they are only a few days old. It is most noticeable when they are in close connection with their mama. In fact, kittens are capable of purring while nursing, and mama kitty typically purrs in response. Perhaps this purring behavior represents a means of bonding between a mother cat and her offspring.

* For territorial reasons: When one cat is entering another’s territory, she may purr to signal to the other cat as a friendly gesture that she’s not interested in aggression.

This last reason is remarkable!

* For pain and pain management:  Most surprisingly, purring frequencies have been shown to stimulate bone regeneration.  Domestic cats purr at a frequency of about 26 vibrations per second, in a range that also promotes tissue regeneration. That may sound crazy but think about this: High-impact exercise promotes bone health for the same reason, because bones respond to pressure by making themselves stronger. In addition to domestic cats, ocelots, cheetahs, and pumas all have the vibration frequency that is therapeutic for bone growth, pain relief and wound healing.

As a mother cat goes into labor, they emit huge purrs, thought to actually release a pain management endorphin. There is some research to suggest that the frequency of the purr has tissue healing properties, so it’s possible that cats purr to self heal, or self soothe.

Purring Is Good – For Many Reasons

It’s naive to think that cats can only purr for one reason—it’s like thinking that people can only laugh for one reason. Humans can laugh out of joy, a desire to be polite, when surprised, in discomfort or in derision—and only context will tell an onlooker which is going on.

Purring isn’t just good for cats, but it’s also healthy for cat owners. Studies show that cats do a better job of relieving stress and lowering blood pressure than other pets. In fact, a 10-year study at the University of Minnesota Stroke Center found that cat owners were 40 percent less likely to have heart attacks than non-cat owners, and purring might play a role in that.

Purring is an auditory stimulus that we attribute to calmness and peacefulness.  That stimulus gives us positive reinforcement and it contributes to the whole relaxation effect when we interact with our cats.

When Purring May Be A Clue To A Problem

Your cat is trying to convey some sort of emotion when she purrs.  Cats don’t just purr to communicate they are content. It’s never safe to assume that if a cat is purring that it is happy and content. As a cat owner, you should always be vigilant.

To determine the cause of your cat’s purring, pay attention to her environment to determine how she’s feeling. Purring during play, during meals, while being petted and during normal routines are usually pretty safely considered the good, positive reasons for her purring.

If your cat is outside her normal environment and purring, she is obviously trying to comfort and soothe herself with something familiar by purring.

*Additionally, and very importantly, if your cat isn’t eating or is listless and uninterested in normal behavior or routine but is purring, that may mean that she is not feeling well and there is most likely something wrong.  This may require a trip to the vet.

The Healing Powers of Purring

Various veterinary studies indicate that cats rarely suffer bone or joint-related diseases, including hip dysplasia, arthritis and ligament problems. Even bone cancers, such as myeloma or osteosarcoma, are almost unheard of in cats. Bone and joint problems may not be the only illnesses helped by a cat’s purring ability. For example, respiratory problems associated with heart disease are almost non-existent in cats.

It has been proposed that purring is nature’s way of endowing felines with an evolutionary healing advantage.

Most of us know that a cat’s purring is relaxing and stress reducing, but science has shown that it can also be physically beneficial. It’s not just the sound of purring that’s important, but the vibration it produces.

Scientists have known for many years that vibrations at specific levels or frequencies cause healing changes in the body. These vibrations can induce bone growth and regeneration, so that bone fractures heal faster and weakened bones begin to strengthen and rebuild. Higher frequency ranges increase production of the body’s natural anti-inflammatory compounds, thereby reducing joint pain and swelling. Evidence suggests that these frequency ranges can repair muscles, tendons and ligaments, which has led to their use in physical therapy clinics, sports medicine, and gyms around the world.