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Why do cats purr when you pet them?

Why do cats purr when you pet them? Let’s find out.

Cat’s purr for two main reasons – soliciting food and healing. In both situations, you might pet your cat and assume this means your cat is purring because you are petting them. However, they could be asking for food or relaxing. Your patting might help cats reach a relaxed state sooner.

My name is Derrick and I am a writer for Simply Cat Care. This is a website dedicated to provided easy-to-read, helpful articles on all things related to cats. I have written this article based on research to give you advice for your cat.

A vet is the main resource needed to learn more about your pet. A vet is your first point of contact if you notice something unusual in your cat.

In this article I will cover the following:

  1. How do cats purr?
  2. Why do cats purr?
  3. Why do cats purr when you pet them?
  4. Is purring a sign of affection?
  5. Why do cats purr and then bite you?

Let’s get into the article.

1. How do cats purr?

First, let’s talk about how a cat actually purrs.

Muscles within the cat larynx provide the basis for a purring sound. When dilated, they tighten around the glottis which surrounds the vocal cords [1].

When a cat inhales and exhales it vibrates against the constricting vocal cords, creating a characteristic purr sound of a cat [1]. The vibrations sound a little like a small motor. 

Purring is also found in other members of the Felidae evolutionary family, including the cheetah and cougar. 

Lions and tigers are part of the Panathenaea family tree which roars instead of purr [2]. This means there was some evolutionary selection pressure that precipitated the emergence of a purr versus a roar in the wider cat family tree. Dogs are distantly related to cats and have no form of purring.     

2. Why do cats purr?

Many people assume that purring is a sign of contentment.

Cats can communicate in a variety of ways with many different sounds, including purring. 

Different sounds can indicate different emotions or needs.

Let’s cover two main reasons cats purr

Hungry Purr

When a cat is hungry, it could start purring.

Termed a ‘solitious purr’, this solicits a response from its mother or owner (e.g. feeding). That means when a cat needs to eat, it will communicate its desire to eat via purring.

When a kitten is only days old, they will begin to purr as a way to help their mother cats locate them for feeding [1]. They use a solitious purr to trigger the owner or mother to respond [1]. The ‘feed me’ purr has an underlying high-frequency meowing sound which has a similar effect to a baby crying.

This is your cat’s way of stating the case ‘Hey, I need food right now!’

Healing Purr

Purring also helps cats reach a relaxed state in their body.

It turns out that the purrs vibrate in the 20-150hz range of sound frequency [3]. This range can stimulate healing in the skin and soft tissue. 

As cats spend a lot of time resting, the purrs might be an energy-efficient way of maintaining strong bones whilst being inactive [3].  

Exercise and general activity maintain strong muscles and bones. When cats are spending a lot of time resting, purrs might be a form of ‘exercise’ that replaces movement.

Cats also purr when giving birth. This may help in relaxing the cat and helping to provide relief from the stress of birth. When cats are in pain or nearing death, they may also purr. The purrs provide a form of stress relief in the animal [4].

Read more about the surprising truth about why cats purr over at this article.

3. Why do cats purr when you pet them?

When you are petting your cat, you might notice your cat purring.

That should mean they are happy right?

It depends. Purring behavior indicates a lot of things. As we learned above, cats use purrs in a relaxed state to help heal themselves.

This can happen in pain as well. For example, even cats that are dying might still purr to help with stress relief [1]. Although this is less likely, it is important to note that purring doesn’t always equate to a happy cat.

Purring is also a language for cats. They create a purr which is a mixture of a high-pitched cry with a purr to get the attention of their human owner. If you hear this type of high-pitched crying meow mixed with a purr then your cat or kitten might be hungry.

They will definitely be happy when the food arrives!

Look out for body language with a tail still and upright (sometimes vibrating). Cats may do this when they want to eat. Your furry friend will also use purring whilst relaxing and staring at you with eyes half-closed. That’s more of a sign your cat is healing and resting.

These additional signs are indicators of what your cat purrs mean.

Why does my cat purr so loud when I pet him?

As I’ve mentioned, a purr can be a sign of pain in a feline.

If you notice a change in your cat’s mood (e.g. they are growling or sensitive to touch) and purring then it might be illness-related. A simple thing like a throat infection might be the cause [5].

If you notice changes in the frequencies of purring, mood, and other unusual symptoms then it is best to see a vet for advice.

Otherwise, the loud purrs could be a sign your cat is especially happy and content.

4. Is purring a sign of affection?

Is purring a sign of affection towards cat owners?

The answer for this is up for debate. A cat may develop affection for the owner, but purring could be a learned association.

For example, my cat may purr as soon as I got home. He knew I would respond with his food.

Research suggests that cat ownership can reduce the risk of death from stroke and heart disease by one-third [5]. Whilst the mechanism for this is speculative, purring could be one key to the benefit of calming us.

Whilst the solicitous high-pitched purr that signals to feed triggers a response to take action, a calming purr might produce a therapeutic response. Cats make us healthier and may purr to keep us happy.

So go ahead, grab a cat and let the purrs work their magic.

Cats may purr if you pat them due to affection, but it is more likely they are relaxed.

5. Why do cats purr and then bite you?

Biting and nibbling also mean a range of things.

If your cat is grooming you (licking), they will sometimes nibble you as well. If you don’t hear any growling or notice any defensive body language then this isn’t a problem. As long as your cat is not hurting you this is ok.

However, if you are patting your cat and they start acting defensively, they might bite harder. Take note of the tail for example. If your cats tail is whipping as they are getting patted, they don’t want you to touch. In other cases, your technique needs adjusting (e.g. don’t approach a cat from behind).

Pay careful attention to all the sounds your kitty makes to understand more about what they are after. Check out more about fascinating cat noises and what they mean in this article.


In this article, I’ve answered the question of why cats purr when you pet them.

Cats make vibrations with the muscles around their vocal cords. These frequencies sound like a car motor.

A feline purrs to get attention for food or other urgent matters.

Called a solitious purr, it has a higher-pitched cry mixed with the sound. You may be patting your cat at this time and associate the purr with happiness, but your cat might want food.

Kitty also purrs when relaxed to heal. The vibrations stimulate the repair of your cat’s body and ease breathing. Your petting might help your feline reach a relaxed state sooner.

There is a debate whether cats are purring due to affection.

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