Why Cats Purr

So, why do cats purr? Let's look at how cats purr and why your cat purring isn't always a sign that your kitty is content.

By Marilyn Krieger of Catster.com

Cats are evolutionary masterpieces of design. They have evolved in such a way that many of their characteristics, including behaviors, are multifunctional — helping to increase the odds of survival. Cat scratching marks territories, it communicates conflicted feelings and it maintains nail health. Cat whiskers feel wind directions, broadcast moods and help cats navigate. But what about cat purring? Why do cats purr and what does it mean when a cat purrs? Let’s find out.

First, how do cats purr?

There are a few theories about how cats purr. The one that stands up the strongest states that cat purrs are produced through a combination of the laryngeal and diaphragmatic muscles along with a neural oscillator. This theory makes sense, because when cats suffer from laryngeal paralysis, they cannot purr. A second theory claims that the small hyoid bone is responsible for cat purrs. The hyoid bone is located between the skull and the larynx. Another theory states that purrs initiate from the central nervous system.

Let’s look at some reasons why cats purr: 

1. Why do cats purr? Newborn kittens and their moms purr to stay safe

Purring is vital for the survival of newborn kittens. The little ones are welcomed into the world by the soft vibrations of their mom’s purr. They are born deaf and blind, but they do feel vibrations. These sweet vibrations are perfect homing devices, guiding newborns to the protective warmth of mom’s body and to their first meals.

Kittens start communicating back to mom and their siblings through purrs. They start purring when they are two days old. When kittens nurse, they cannot meow, so they show their contentment by purring. Mom purrs back comfort and safety.

There is another way primal purring ups the odds for survival. Cat purring helps keep neonates safe from predators. Hungry predators are more likely to detect cries and other vocalizations than the vibrations of purrs.

Cat moms purr when they give birth. In addition to benefitting kittens, purring helps the mothers in a number of ways. The new moms are vulnerable and cannot defend themselves when they are giving birth. Painful cries attract danger. Instead of crying, they purr. Purring releases endorphins, reducing pain while simultaneously reassuring the newborns without luring unwanted visitors.

2. Cats purr when they want attention

Cat parents are familiar with the relaxing purrs of cats as they cuddle and stroke them. These little purr machines exude contentment, with the added benefit of uplifting the moods of the people who adore them while lowering their blood pressure.

Many kitties quickly figure out another basic benefit of purring — soliciting food and attention from their favorite people. Since most cat-parents lavish attention on their cats when they purr, cats often purr when they want affection and treats.

3. Cats purr when they are stressed, in pain or sick because cat purrs have healing powers

Not all cat purrs are purrs of contentment. Cats purr when they are stressed, in pain or severely ill. Often, cats at the end of life will purr. Cats enter life and leave life on a purr.

What makes a purr a purr has tickled the curiosity of the scientific community for years. Studies find that purrs oscillate at a low frequency of 25 to 100 HZ. These frequencies promote bone healing and ease muscle pain. Clinical trials of people receiving ultrasound treatments have proven that low-frequency/intensity ultrasound accelerates healing in fractures. Purrs reassure and soothe, they promote healing, and reduce pain.

There are also reports that cats heal faster than other animals that do not purr, and that purring releases endorphins. Endorphins reduce pain while healing takes place. Purring is the feline equivalent of expensive ultrasound treatments, without medical bills.

4. Cats purr for some low-key exercise

It is hard to imagine that relaxed, purring cats are in the midst of low-intensity exercise sessions. Felines are experts at conserving their energy through naps and lounging. According to Dr. Leslie Lyons, world-renowned genetics researcher and professor at the University of Missouri College of Veterinary Medicine, the vibrations from purring may stimulate muscles and bones without the cat extending a lot of energy and effort.

Something for you to think about the next time you cuddle with your little purr-machine. Looks are deceiving — in reality, she might be heavily engaged in calisthenics.

And FYI: Cats do not have the monopoly on purring

Although our domestic cats are not the only animals who purr, their purrs are unique because they are the only ones who purr while they inhale and exhale. Not all members of the Felidae family technically purr, though. Lions, leopards and tigers roar, but they do not purr. Cheetahs and cougars are examples of big cats who purr.

Many other animals purr as well. The mechanisms that produce the purr vary between species, as do the meanings of their purrs. Gorillas, raccoons, rabbits, ring tailed lemurs, tapirs, elephants and hyenas are examples of other animals who purr.

Cat purrs are complex and powerful. They comfort cats and their people. Their vibrations heal, produce pain-relieving endorphins and ensure the survival of newborn kittens.


I have a rescue cat from Brother Wolf. She is about 2 1/2 years old. She meows loudly, like a roar sometimes, so nothing is wrong with her vocal chords. She is very loving. She looks very content when I am scratching her neck and cheeks and the top of her head, which she loves. She sleeps with me and follows me around all day and wants to be loved. However, she doesn't purr!! Any ideas about why? Thanks.

Many cats purr so quietly that you can't hear it, or she may not have learned to purr at all if she was an orphan. She's showing her happiness through following you around and wanting attention - so don't worry! She sounds like a very happy girl.