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?

Before we answer, “Why do cats purr?” let’s talk about how 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.

So, why do cats purr? Let’s look at some reasons: 

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

Another answer to, “Why do cats purr?” 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 answers to, “Why do cats purr?” are as positive or obvious. 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

Another surprising answer to the question, “Why do cats purr?” Cat purring is actually a form of kitty 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.

The bottom line on, “Why do cats 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.

Thumbnail:  Photography ©infinityyy | Thinkstock. 

This piece was originally published in 2015.

About the author

For more articles and feline facts, follow Marilyn on Facebook!

Got a cat behavior question for Marilyn? Ask our behaviorist in the comments below and you might be featured in an upcoming column. If you suspect a behavioral problem, always rule out any possible medical issues that may be causing the behavior by first having your cat examined by a veterinarian. Marilyn can also help you resolve cat behavior challenges through a consultation.

Marilyn, a certified cat behavior consultant, owner of The Cat Coach, LLC, solves cat behavior problems nationally and internationally through on site, Skype and phone consultations. She uses force free methods that include environmental changes, management, clicker training and other behavior modification techniques.

She is also an award winning author. Her book Naughty No More! focuses on solving cat behavior problems through clicker training and other force-free methods. Marilyn is big on education — she feels it is important for cat parents to know the reasons behind their cat’s behaviors. She is a frequent guest on television and radio, answering cat behavior questions and helping people understand their cats.

Read more about cat sounds on Catster.com:

• 9 Weird Cat Sounds and What They Mean
• 6 Cat Meow Sounds and What They Mean
• 10 Common Cat Noises — and What They Mean