Cat Communication: Why Do Cats Purr?

The sounds a cat makes vary, from the recognisable meowing and hissing to the less frequent chirping and caterwauling. One other sound you probably find mysterious is the often misunderstood purring. Misunderstood because the low, rhythmic tone does not always mean your cat is content.

Why do cats purr? Here, we decode the many meanings behind this feline sound.

What Does It Mean If a Cat Purrs​?

Kittens purr after a few days of being born. Born blind and deaf, kittens use the purring to let their mothers know where they are and let them know they’re hungry. This form of cat behaviour continues into adulthood, shifting the responsibility of interpretation to you, the cat’s new guardian.

There’s a lot more complexity to a cat purring than comfort and contentment because it is one of the ways they communicate.

Here are the reasons some cats purr.

They’re happy.

Perhaps the most popular notion as to why cats purr so loud​ is that they’re so comfortable and content. Maybe they’re sitting on your lap or beside you on the couch, and you're stroking them. Maybe they’ve just had the best cat food. Whatever it is, the purring communicates their satisfaction.

The purring is usually accompanied by body language, such as kneading something soft, such as a cushion or blanket.

They’re nervous.

Some purrs are not at all a declaration of satisfaction; some convey anxiety and stress. The cat may be reacting to a nerve-racking event, like loud noises, a trip to the veterinarian, or an abrupt change in the environment. 

Do cats purr when they are scared​? Yes, some cats may purr when encountering a stressful situation. Flattened ears and tucked tail typically accompany the vibrating sound when a cat is scared.

When your cat purrs after a stressful time, they’re likely self-soothing. It’s a coping mechanism that was observed during a study, which was published in the Journal of the Acoustical Society of America. The study revealed that domestic cats and big cats could purr at certain frequencies suitable for pain relief.

They’re in pain.

Do cats purr when sick​? As the study in the Journal of the Acoustical Society of America presented, cats do purr when they’re sick.

The low and steady vibrations are thought to heal. Other than relieving pain, the frequencies between 20Hz up to 150Hz are said to promote bone growth as the pressure hardens the bones. 

The purring can also be beneficial for humans. The frequency of a cat’s purr aligns with vibrational and electrical frequencies used in therapies for bone healing, pain relief, reducing swelling, muscle repair, improving joint flexibility, easing breathing difficulties, and supporting wound recovery

When your cat sits on your lap while you're nursing a cold or recuperating from surgery, they may be helping you heal as they purr.

They need your attention.

Sometimes, a cat’s purr means they’re trying to get your attention. If you’ve been taking care of your cat for a long while, you’ll know the signs and what they mean. 

They may be signalling their approval when you bring them a new toy from a cat accessories store. Some very smart cats can even persuade humans into giving them treats by concealing a cry within a purr; these cats can modify their purring to mimic a baby’s cry, with a purr that’s more urgent and less pleasant.

But in general, if your cat purrs:

• First thing in the morning as they wait on your bed, waiting for you to wake up, or by the refrigerator when you come into the kitchen, they want to be fed (or they’re wanting a snack).

• As you walk in the door, they’re greeting you and welcoming you back into the home.

• When they rub their face against your leg or your hand, they want you to pet them; they’re asking for affection.

How Do Cats Purr​?

The initial explanation behind the “how” links the purring to blood flow into the inferior vena cava. It’s the vein responsible for carrying deoxygenated blood to the right side of a cat’s heart. But further research now suggests that the low vibrations come from the muscles in the cat’s voicebox, or larynx.

As the muscles move, they constrict and dilate the glottis, which surrounds the vocal cords. The vibrating air from the inhaling and exhaling results in the purring.

How long can cats purr for? Some cats can purr continuously as they’re sitting on your lap or when they’re enjoying cat treats. But some seemingly non-stop purrs could be a red flag. If the continuous purring comes with an unusual behaviour in your cat, you might need to take them to the vet.

Why Some Cats Don't Purr

Not all cats can purr; in the wild, cheetahs, pumas, tigers, and ocelots can purr, but the lion cannot. The larynx of lions may not be stiff enough to produce the purring sound.

The same thing might be the case for domestic cats that don’t purr. Anatomical differences could be the reason some cats do not produce the low, vibrating sound. You might not need to worry if your cat has never purred since they were a kitten. Cats are super smart, so they’ll find another way to communicate with you.

If your cat has suddenly stopped purring, they may be telling you something’s wrong. They might be stressed out or they may be unwell. Any abrupt change in your cat’s communication style or behaviour calls for a visit to the vet. 

How to Make Your  Cat Purr

Although there’s no guarantee to make your cat purr if they’ve never made the sound, you could still try a few approaches. Ideally, start when they’re young.

You can encourage your kitten to purr by stroking them, finding out how they like to be petted. Gently scratch them behind the ear, on their head or wherever they allow you to stroke them. You can also try to cuddle and nap with them. Make sure your kitten has all the cat accessories and supplies they need.

Anything you can do to gain their trust and help them feel comfortable may encourage them to purr.

Why do cats purr? The answers are more complex than your cat feeling happy and content. To understand what your cat is telling you, pay attention to the behaviour that comes with the purr. It’s the full picture that reveals their true message.