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Why And How Do Cats Purr?

lovely kitten playing with a flower

Do you wonder why your cat starts purring when you touch it? Well, cats do purr when they are happy, and of course they become very happy when you pet them. Let’s see why and how do cats purr?

However, not all cats can purr. According to the Carnegie Museum of Natural History, big cats like lions, leopards, tigers and jaguars can roar, but they can’t purr.

Smaller cats like cougars, bobcats, ocelots, lynxes, pumas, wild cats and domestic cats do purr, but can’t roar.

How do cats purr?

When a cat is happy, its brain starts sending signals to the laryngeal muscles in its voice box to start vibrating. The same laryngeal muscles act like a valve by opening and closing the glottis (a space between the vocal cords).

This movement allows air to flow past the cat’s voice box, and this is the reason why cats purr both when inhaling and exhaling air.

However, scientists don’t agree 100% why do cats initiate purring.

There are three different theories that are trying to explain in a different way the reason behind this behaviour.

1. It’s a voluntary act initiated by the cat’s nervous system

Some scientists consider that cats start purring due to a signal sent by their nervous system. This means that purring in cats starts involuntarily and the behaviour is dictated by their feelings in that moment.

2. Is started by a neural oscillator

A different study suggests that purring is ignited by a neural oscillator in the cat’s brain.

3. Purring is started by the release of endorphins

A third study says that purring in cats is started by the release of endorphins in the cat’s brain.

When a cat is happy or feels pain, its brain starts releasing endorphins to increase pleasure or reduce pain.

How do cats feel when they purr?

It seems that cats don’t always purr when they are happy. Sure that you can hear the purring sound when petting or feeding them, but they do purr in other situations too.

Purring starts when the cat is very young. Nursing kittens do purr to let their mother know that they are well, because they can’t drink milk and meow at the same time.

The behaviour appears for the first time when the kittens are very young and is used to show the mother that everything is fine with them, and also to create a bond with their mom.

However, cats do purr when they are happy, but they can also start purring when they are sick, upset or injured.

It seems that even dying cats purr, which shows that they could be in great pain due to an injury or because they are sick.

Female cats also purr sometimes when they’re delivering kittens.

Frightened cats may purr just to show peaceful intentions and to signal that they will not attack.

Older cats may purr when they get around younger cats just to signal that they are friendly.

How strong is the sound created by purring?

Due to the rapid opening and closing of their vocal chords when they purr, cats can create a sound with a frequency between 25 and 150 Hz (hertz).

It seems that these sound frequencies can improve bone density and act as a natural healing mechanism.

This would be the reason why cats purr when they are sick or injured because the frequency of the sound created by purring can repair bones, heal wounds and relieve pain.

Why do cats bite you when they are purring?

Like all cat owners know, sometimes our friendly felines will bite us when we are trying to pet them.

At first glance, that doesn’t make sense because they bite exactly the person that feeds and loves them the most.

Some cat lovers call this behaviour “love bites”, but vets know better and call this behaviour “petting-induced aggression”.

cats are still wild

Cats are cute but in many ways still wild, image source: pixabay.com

Petting-induced aggression is different from a direct attack triggered by your behaviour (when you are trying to pet a cat that doesn’t know you).

Love bites or petting-induced aggression produces less damage compared to a direct attack, but they do occur and the owner may be surprised or frightened by such behavior.

The problem appears when the cat seeks attention, you start petting it, and suddenly it turns to bite you.

Theories about petting-induced aggression

There are several theories in which cat experts are trying to explain this strange behaviour in some cats.

1. Cats are solitary animals

The ancestor of the modern domestic cat was maybe a solitary animal that lived only in the wild and away from human settlements.

Despite the fact that you keep your cat in the house along with your family, she might want to show you that she isn’t domesticated yet, so when you are showing your affection, she will automatically bite you to make you understand that she is still a wild and solitary animal.

2. Your cat doesn’t like you that much

A different theory says that some cats may actually experience prolonged petting negatively, and biting is a reaction to that.

Overdone, petting might be irritating for some cats.

Or maybe you are petting the cat by touching some vulnerable parts of its body, such as the belly or the tail (cats don’t like that).

Biting could also happen if the cat gets scared or gets excited and decides that the petting session is over.

You have to remember that your cat is still a predator that might ambush your ankles when you are on your way to the bathroom late in the night, or might even bite you when you are trying to pet them to show your affection.

3. Your cat wants to remember you that she is still a bloodthirsty predator

The final theory is somehow related to the previous one because it refers to the same subject, cats are still wild, and they have never been completely domesticated.

The strange behaviour is explained as a sudden switch between enjoying the moment with you and blood thirst.

What you can do with a cat that suffers due to petting-induced aggression?

Some say that these cats are a lost cause, but I’m saying that we only have to pay more attention to the cat needs.

You don’t have a cat just to make you feel good, you have to think from her perspective as well.

If you have a cat that doesn’t like to be excessively petted, you only have to stop petting her or him for at least one week. After that, before feeding, when it approaches to you, you can shortly and gently pet its head between the ears and a little behind them, but only for two or three seconds. After that you can feed it.

You can learn this way that two or three seconds are just enough for your cat.

If she starts biting you when you are trying to pet it even for a short time, I suggest you to stop petting it for a while or at least until it will come to you alone to seek affection.

Only in that moment you can gently pet her or him on the back, but again, only for a short time (a couple of seconds).

However, if you can’t stop this behaviour in your cat at all, I suggest you to consult a veterinarian.

A professional can help you figure out what triggers this behaviour in your cat and what you can do to reduce or stop it.

cute tabby cat

Cute tabby cat watching you, image source: pixabay.com

My personal experience with a cat suffering from petting-induced aggression

I had a tomcat in the house for a couple of years (I raised him since he was only a kitten), and he used to attack me every time I petted him for more than five seconds.

I never touched him on the belly, because I realized that he doesn’t like that at all.

However, that cat is half wild because it prefers to live outside almost all the time.

I talked with my neighbours and they told me that my cat does not accept the presence of people very much (they can’t touch him at all because it reacts aggressively), and prefers to live along with other neighboring cats hunting birds and rodents in the area.

From time to time, he returns home to spend some time with me and my family, and only then we can feed him and of course, pet him for a couple of seconds, but after that he leaves again to wander for another one or two months.

Article written by:

Darius Savin is a lifelong animal lover and protector and the chief editor of Checkmember. He writes and edits articles and is also the creator of the distribution maps for all the creatures featured here.