Why Do Cats Purr?

It’s the sound that all cat owners are so used to and in fact, love to hear. While most people assume that a purring cat means a content cat, surprisingly, this may not always be the case and the mechanisms and functions of purring are actually still being figured out today.

It appears that the laryngeal muscles are involved in the purring sound; specifically the opening and closing of the vocal cords. But it’s not entirely understood.

If it is not always a sign of a happy cat, then, what else could it be?

cute purring cat

How Does Your Kitty Purr?

A cat’s purr is one of the most mysterious natural occurrences. This is because there is no purring organ unlike with the other vocalizations of various animal species.

Veterinarians, biologists, and researchers have always wondered how a cat’s purr is done. There have been various theories regarding the production of this sound.

An older theory on purr production says that the purring sound is a consequence of blood flow turbulence in the kitty’s chest. But there is very little evidence regarding this theory.

Another theory – the most credible one so far – suggests that a kitty’s purr is the action of the muscles in the larynx and the pharynx combined with a neural oscillator.

As a kitty inhales and exhales, the amount of air passing through the larynx and pharynx alters at high speeds; something that roaring cats and other animals, including us, are unable to do. How is this possible?

Your house tabby, small wildcats, cheetahs, snow leopards, and cougars have a special timer in their brains that sends about 25 electrical pulses per second to a certain muscle in the kitty’s voice box; allowing the vocal folds to swing together at one pulse and swing apart at another pulse.

A feline’s purr is also different from other mammals’ purrs. Rabbits, for example, use their front teeth rather than their laryngeal folds to purr. Elephants don’t use neural signals for muscle control.

Reasons Behind Cats’ Purring

Like human voices, cats’ purring sounds vary between individuals. Some are so low that they can be felt rather than heard, while others are loud enough that you can already hear your kitty purring across the room while you stand in the doorway.

But why do they do this? Let’s find out:

1. Art Of Newborn Communication

Kittens begin to learn how to purr when they are just day days old from their mothers. It’s believed that this functions as a type of communication between the newborn and the mom which means they’re saying “I’m healthy and okay!”

Additionally, since kittens are born blind, the mother’s purring helps them locate her in the world and also functions as a bonding mechanism between the two. They already have their sense of touch which means that they are sensitive enough to suss out their mother’s vibratory purrs.

Today, a mama cat’s purring leads wayward newborn babies to their mother’s teats. In return, the kittens learn how to purr to communicate with both their mama cat and their littermates.

It’s also believed that purring has an evolutionary advantage over, for example, meowing for attention as this would attract predators in the wild.

So purring is a more low-key form of communication, especially for very vulnerable kittens. This function of purring as communication extends into adulthood and into their relationships with humans.

It’s possible that purring is a kitten-specific trait that is simply retained into adulthood. Kneading for their mother’s milk, for example, is a behavior that many cats will continue to display well into adulthood and often is paired alongside purring.

2. Happiness and Contentment

Although not limited to contentment, purring definitely is something cats do when they are relaxed. When you see a cat with its eyes closed, tail up, soft fur, and purring on a person’s lap, it’s pretty easy to figure out that the purring means it’s happy.

Cats often purr when someone starts petting them as their way of saying “I like that, please continue.” Research has found that purring actually releases endorphins that are self-soothing. So, it makes sense that cats purr while enjoying cuddles on the lap of their owners.

In general, cats purr during positive social situations: while nursing (both kitten and mom), grooming, and socialization. In fact, content purring is actually rarely done when the cat is alone.

As baby felines develop bonds with their mama cat, they also develop the art of kneading, which helps release milk from their mother’s nipples. The repetitive actions of kneading, drinking milk, and exchanging purrs with the mama cat will eventually become part of your pet cat’s instinct.

As your little tabby grows older, it may be weaned from its mother but the instincts still remain. Whenever it feels happy and contented, like when it’s sitting on your warm lap, it may instinctively express its contentment through kneading and purring.

3. “Feed Me Hooman” - Attention and Relaxation

Kittenhood develops a lot of instinctual habits that have a lot of different meanings. Some of these habits become specialized and modified when a cat establishes a new bond; like with its human.

Many cats also purr to solicit attention or if they want something from people. They’ve essentially learned that it’s a good way to get what they want.

Lots of cats will purr if they want food or to play and some will even modify their purr into what’s known as a ‘socialization purr’. This combines a purr and a meow and it’s been seen that cat owners are very alert to the call and respond in a similar way that a parent might react to the cry of their baby.

Coupled with a bit of tail rubbing on our legs, it may be saying something like: “I’m hungry. Feed me, hooman.” Weak as we are to those cute purrs, it is no surprise that our kitties own us and not the other way around.

4. Purr Therapy - Stress and Pain

On the other end of the spectrum and what many people may not know is that cats also purr in negative situations such as when stressed out or even in pain.

As mentioned above, purring can help a cat feel better. So, when they are feeling stressed, when they are in pain, when they feel frightened or when they feel threatened, it’s an attempt to resolve these.

This is also evident when a mama cat goes into labor. By purring, its body releases endorphins that help ease the labor. In a way, it’s akin to a person trying to distract themselves from anxiety.

Some literature even talk about the so-called ‘purr therapy’ where cats have been observed to purr next to one another when one of them is injured. Veterinarians also have seen that cats purr when they are very sick, or even in some cases close to death.

This is also related to the fact that cats hide when very ill as they think they can escape the discomfort and pain. They also do this when they do kitty massage (yes, all that kneading and purring).

Aside from the endorphins and mental therapy aspects of purring, there may be physical healing properties associated with purring as well. Studies have found that the frequency of the vibrations associated with purrs – around 24-140 vibrations per minute – can help stimulate bone strengthening and healing, as well as the healing of muscles and wounds.

It is similar to high-impact exercises as well as martial arts training. The consistent pressures applied to the bones and the muscles condition the body again and again; making them stronger.

Additionally, purring may help to lessen swelling and ease breathing. This means that purring not only is beneficial for a cat’s health in terms of bone strength being maintained, but it can actively heal injuries.

This is also why a cat’s purr is believed to be helpful for humans. Studies have shown that cats actually lower the blood pressure of their owners, reduce stress, and decrease chances of heart attack, so the powers of purring can extend past the individual cat.

5. The White Flag

Your neighbor’s kitty may purr to your own tabby when they meet. This is another way of saying “Hello! I come in peace.”

A cat’s purr may also mean that it is hurt, or for very old cats, that it is dying. It could either mean “Please be relaxed and move on,” as if it’s trying to be strong for its human, or it could be saying “I may be harmless and weak, but I am still here.”

6. Fear

Strangely enough, cats will also purr if they’re under acute fear. A fearful cat is an incredibly elevated state of physiological arousal – meaning, the adrenaline and the heart rate are both increased.

As mentioned previously, purring acts to calm both of these down. Purring, in this case, is an almost unconscious reaction to their frightened state and again, serves as a way to comfort themselves.

Purrfect Way to Stop Purring

A cat’s purr may be soothing for us humans but it can be a liability during health checkups.

Because a kitty’s purr can help ease their nerves, cats going to the vet may purr in the middle of a health examination. This can be detrimental to a veterinarian trying to follow the kitty’s heartbeat and breathing with the stethoscope.

What some veterinarians do – and for some strange reason works – is turn on the water faucet. The running water often distracts cats long enough to make cats stop purring.

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