Why Cats Purr

Most people associate cats purring with happiness and calm, and that's often true. But contentment isn't the only reason why cats purr. Understanding the different reasons your cat purrs can help strengthen your bond and better support their needs.

Kittens & Mother Cats Purr to Bond

Purring is a deeply ingrained instinct, and one of a cat’s first communication methods. Mother cats purr to soothe their kittens, just like a human parent may hum or sing a soft lullaby to comfort a baby. Purring can also help kittens find their way to a meal. Kittens are blind and deaf for the first week or two, but they can feel vibrations from their mother purring.

Kittens can start purring when they’re just a few days old, and most kittens are purring by their third week. Kittens purr to signal to the mother cat that they’re safe and content. Kittens may also purr to self-soothe or seek attention (and milk) from the mother cat.

Cats Purr When They’re Relaxed & Happy

Cats often purr to express contentment and satisfaction. Cat parents may notice their cat purring while cuddling, being stroked, playing, and even while eating. You can identify happy purring by observing your cat’s body language for signs of happiness, positive excitement, or playfulness.

Some Cats Purr When They Want Food

A study published in Current Biology found that “feed me” purring sounds different from other types of purring. In this study, even non-cat parents were able to distinguish between the different purr sounds. When cats are purring to solicit food, there’s a plaintive ‘mew’ in it. Scientists speculate that over millennia of domestication, cats learned that humans respond to infant distress cries with feeding and other care behaviors. So cats have incorporated a similar sound into purring to take advantage of this sensitivity.

Purring for Pain Relief & Healing

Cat also purr when they are anxious, ill, or injured. Cats purr when they’re giving birth, dying, or otherwise in pain because purring releases endorphins—hormones that relieve pain and stress. Cats may also purr in uncomfortable situations as a self-soothing behavior, like a toddler sucking their thumb.

Cats Purr to Heal & Maintain Health

A study published in The Journal of the Acoustical Society of America found that domestic cat purrs fall in the frequency range of 25 - 150 Hz. This is the same vibrational frequency used to speed healing of bone fractures, wounds, joint/tendon injuries, edema (swelling) and dyspnea (shortness of breath). Scientists believe that cats have evolved these specific purr frequencies as an internal healing mechanism. This could be where the myth that ‘cats have nine lives’ comes from.

Purring May Help Heal People

A study published in the Journal of Applied Physiology showed that in-phase chest wall vibration (IPV) at 100 Hz reduced the intensity of dyspnea in people. This suggests that a cat purring on their human’s chest at the same vibrational frequency could offer similar benefits.

Another study published in the Journal of Vascular and Interventional Neurology showed that cat parents have a significantly lower risk of heart attack and stroke, compared to people who were never cat parents. This has fueled speculation that cat purring may provide a healing effect to humans.

There’s no scientific evidence for this, but the internet has plenty of anecdotal reports from people who say that lying down with a purring cat by their head can heal a migraine. In any case, relaxing with a purring cat is practically guaranteed to provide stress relief, which can only make you feel better!

Stimulation & Overstimulation

As a cat parent you’ve probably noticed your cat purrs when you’re stroking them, and it’s believed these purrs express pleasure. On the other hand, plenty of cat parents wonder why their purring cat suddenly bites the hand that pets them.

Sometimes called ‘petting aggression,’ it’s believed that at a certain point your cat gets overstimulated and is telling you they’ve had enough for now. Cats are very sensitive to touch, so it’s important to tune in to your cat’s purring and body language to sense when they’ve changed gears from ‘yes, please’ to ‘please stop.’

It’s also common for cats to purr while kneading. Purring and kneading are both actions could indicate happiness or stress, depending on the context and your cat’s body language.

How Much Purring Is Normal?

Wondering ‘how much should a cat purr’ is like asking ‘how does a normal cat behave?’ The answer, of course, is that every cat is different. Some cats purr more than others, and some cats don’t purr at all. If your cat never purrs and the vet says they’re healthy, it’s likely due to individual physiology - their vocal cords and/or respiratory system might not be optimal for purring. The important thing is knowing what normal purring means for your cat, so you can notice if it changes. When there’s a sudden or significant change in any of your cat’s behaviors (including purring), you should consult your vet to see if it could be caused by an underlying health issue.

Why Does My Cat Purr so Loudly?

How loudly your cat purrs depends on the size of your cat and its vocal cords. Some cat breeds are also known to purr more loudly than others, such as Oriental Shorthairs, Bengals, Sphyx, and Maine Coon cats. Then again, the Guinness World Record for the loudest domestic cat purr is held by an ordinary-looking British shorthair, so it really is an individual trait!

You may notice your cat’s purr getting louder and deeper as they age. This is because vocal cords develop and strengthen with use, which produces a louder purring sound. Purring volume can also increase with intensity of feeling, whether positive and negative.

Finally, it’s possible that a respiratory sickness could make your cat’s purr louder, so take them to the vet if there’s a sudden concerning change in volume, or if their purring sounds congested.

Purring: A Common Behavior with Individual Quirks

Purring is a natural impulse, and cats tend to purr when they are feeling pleasure (stroking, feeding, resting) or pain (anxiety, injury, overstimulation). Getting to know your cat’s unique purring habits will help you better understand your cat and support their well-being. To learn even more, check out our blog explaining why cats sleep so much!