Why do Cats Purr?

A sound that even those that don’t have cats in their direct surroundings will recognize, purring. A purring cat is often automatically perceived to be a happy cat, as that is what is often taught from early on. That purring doesn’t always mean happiness, and may even indicate pain, may come as a surprise to some. Purring is an interesting behaviour, which is used in different scenario’s, and even may have healing properties. So, let’s have a closer look at the interesting science behind purring.


Cats can make a wide range of sounds, such as chirping, growling, and chattering, but purring is the most known one by far. The purring sound is formed in the larynx, also known as the voice box. When the laryngeal muscles move, they constrict and dilate the middle part of the larynx, also known as the glottis, which is where the vocal cords are located. When the cat exhales and inhales, the air that passes through the glottis vibrates, which results in the purring sound. Domestic cats purr at the frequency of 25 to 150 Hertz. Purring is often a sign that a cat is feeling happy, though cats can also purr for other reasons.  

Purring in Kittens

Kittens start purring as early as just a few days old, even before they are able to hear and see. Purring between kittens and their mother is a form of communication, and a bonding mechanism. A mother will purr at her kittens as it provides comfort, and the kittens will purr at their mother to let her know where they are, and to signal they want to be fed. 

Purring for Food

Purring for food is also seen in adult cats, and it’s not uncommon for them to display purring around feeding time to direct their owners to prepare food. A study done by the university of Sussex, found that cats often display a special purr when wanting to be fed. This special purr is different that of a “normal” purr, and triggers a sense of urgency, making it hard to ignore by pet owners. This special purr has a high-frequency element embedded in it which is similar to that of a cry or meow, prompting owners to take action sooner as it activates our innate human nurturing instincts. 

Pain and Stress

While cats often purr when feeling happy and content, the total opposite might also be the case. Purring is also seen when a cat is experiencing pain, discomfort, nervousness, and/or stress. They do this for various reasons. 

Firstly,  purring releases endorphins in the brain. Endorphins block the perception of pain, and hence act as the body’s natural painkiller. Endorphins also increase feelings of well-being. So by purring, a cat can help relieve their pain, and it helps them with self soothing.  

Secondly, research suggests that domestic cats, and some species of big cats, can purr at frequencies that help with healing injuries, and reduce inflammation. This may also explain why some cats purr more loudly when recovering from an illness or injury.  Purring acts as vibrational therapy that aids their recovery. 

Purring for humans

Purring is not only beneficial to the cat, but research suggests that it’s also beneficial to us humans. When a cat purrs, it not only releases endorphins in their own brains, but also in that of the humans that can hear the purring. These endorphins released in our brain, helps us decrease stress hormone levels, which in turn is beneficial for lowering blood pressure and healing. 


So how do I know why my cat is purring?

Surprised that purring doesn’t always indicate happiness? You are not alone. So, how can you tell why your cat is purring? Purring, like any other behaviour displayed, should always be looked at in combination with other signals your cat sends, and in context with the situation. When your cat is laying on your lap getting stroked, and is displaying overall relaxed body language signals, chances are big they are purring because they are happy and content. However, if your cat is showing other signals that may indicate discomfort, such as hiding away, don’t let purring throw you off thinking they are fine, as there may actually be something wrong. 


Purring has more depth and significance than one may initially believe. It’s used in many different situations, and can have different meanings, from contentment, to pain, to stress. Besides communicative purposes, purring is believed to have healing aspects. And by being aware of all the purposes purring can be used for, we can understand and take care of our cats better. 

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