Why do cats purr (and when is it something to worry about)?

Who doesn't love it when a cat purrs? People often think it means a cat's happy, and while it can mean that, it isn't always the case.

The truth is that purring is a unique characteristic that can mean many things. For example, your cat may purr if you pet it because it's happy, but at the same time, they can purr after a stressful event; in truth, it's a complicated expression.

Here, we discuss how cats purr, why they do it and some common misconceptions about it.

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How do cats purr?

The mechanics of purring are complex, and subtle differences can indicate completely different emotions. It's a bit like a human's sigh: a sigh can be good, but sometimes, it can express impatience or negativity.

How cats purr is still a contentious topic, with a 2023 study completely changing how researchers thought kitties made this sound.

Generally, the research so far indicates that cats purr through a four-step process:

1. The central nervous system sends a trigger

2. Vocal cords respond to the trigger and vibrate slowly

3. Larynx muscles contract at roughly 20-30 times a second

4. The cat passes air, making the sound

But the study we just mentioned indicated that cats could purr without the involvement of larynx muscles, so, bizarrely, we still don't really know how cats purr. The plot thickens.

Why do cats purr? Common reasons

Thankfully, we understand the why more than the how. Here are the key reasons why cats purr:

Contentment and relaxation

So, we automatically assume purring means a cat's happy and, for the most part, that's true. While it can signify other things, cats purr when they're feeling content and relaxed.

If your cat never purrs, we wouldn't look too much into it, but it can signify they're struggling to feel content. We wouldn't look at it in isolation, but if there are other signs of anxiety or depression, then it's worth chatting to your vet about it.

Our article on increasing your cat's happiness can help.

Communication with humans

Sadly (or maybe thankfully) cats can't talk. But they do communicate with body language, meows and purrs.

Purrs may be a way for a cat to communicate that it has bonded with you, and helps them tell you that they're enjoying the interaction.

So, if a cat purrs in your presence, we think it's safe to say they consider you a friend.

Healing and self-soothing

Cats can sometimes appear lonely and reserved. While they do tend to like their "me time", a lot of this has to do with self-soothing and healing.

Research has found that purring operates at 25 to 150 Hertz (Hz), which is a frequency associated with improving muscle and bone health.

Plus, the emotional impact of purring (the way it promotes contentment) could be a cat's way of recovering after stress.

Illness

Cats can purr when they're ill or in pain, too. Purring may be their way of communicating that they need care or are seeking comfort.

They want attention

Cats will purr when they want some fuss. Generally, that'll go away if you pet them, or they may purr when rubbing their face or body against you or another cat.

If you've ever wondered "Why do cats purr when you pet them?", this is why: they've got your attention and they like it.

Why do cats purr loudly?

Volume is important when a cat purrs, too. Generally, a louder call may signify increased:

• Anxiety

• Desire for comfort or attention

• High excitement

• Surprise

Excessive vocalisation in cats can mean they need help with something, like separation anxiety.

Why do cats purr and knead?

Kneading - also known as "pawing" - is when cats push their paws into a soft surface. Commonly, cats purr when they do this.

It's because the reasons for kneading overlap with a cat's motivations to purr, namely:

• Comfort and self-soothing: Like purring, cats knead when they're feeling good and use it to relax. 

• Marking territory: As we mentioned in our cat sweat article, they have scent and sweat glands in their feet, meaning kitties may use kneading to mark territory.

• Stretching and relaxing: They may knead to stretch out and relax, a bit like a cat version of yoga.

The biological reason for a kitten kneading is replicating how they stimulate milk production from their mother. It makes sense, then, why they purr at the same time.

Why do cats dribble when they purr?

This normally happens when a cat purrs and is very relaxed. It's involuntary and occurs due to a mix of muscle relaxation and endorphins.

But excessive dribbling is a warning sign and can mean your cat is dealing with something, like allergies, dental problems or seizures.

We recommend seeing a vet if your cat drools or dribbles a lot.

Cat insurance for when you need (and when you don't)

As you can see, purring is normally something good. But it can mean something's up too.

It's why we recommend having a good relationship with your vet and getting regular health check-ups, as this can help you spot issues early.

Cat insurance can help with that. With up to £15,000 vet fee cover, 24/7 video access to a professional with FirstVet and a host of ManyPets Perks, we'll be there when you need us (and when you don't).

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We know your cat knows best. But let's keep them protected from any unexpected accidents or illnesses - just in case.

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