Purring, a gentle vibration that domestic cats make as they breathe in and out, is unique to cats and cat-like animals. Cougars, cheetahs, and some other big cats also purr; so do civets, genets, and mongooses. But why do cats purr?
“It’s one of those behaviors that we mostly understand, but not quite,” he said. Mikel Delgado, (opens in a new tab) a certified feline behavior consultant at Feline Minds, told Live Science. “The purring is probably reflexive, like breathing.”
The comfortable murmur of a cat’s purr is one of life’s little joys for cat owners. But is that also true for the cat? Yes, cats usually purr when they feel good. Whether sitting on your lap or lying in the sun, a purring cat is usually a happy cat.
“Ninety percent of the time, purring is positive,” Delgado said. “It means that your cat is experiencing pleasure. He is happy, content and feels safe.”
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Other reasons why cats purr
But research suggests that cats purr for other reasons, too. One is related to survival. Kittens are born blind and deaf; They begin to purr a few days after birth. In the wild, purring is safe because it is silent, so predators are unlikely to hear a kitten purr.
At first, purring helps kittens stay close to mother cats, Dr Kate Anderson (opens in a new tab), a veterinarian and professor at Cornell University, told Live Science. “They actually find their mother purring, and their mother controls them and then purrs back,” Anderson explained.
Kittens also purr while nursing. “The purr can even bond between the mother and the kittens,” Delgado said.
Cats continue to purr when they grow up. “They will purr with another cat they are friends with,” Anderson said.
Cats often purr while grooming each other, when “there’s some nurturing behavior going on,” Delgado said. Domestic cats purr around humans and family dogs. Cats also purr while resting, eating, or enjoying time alone.
Also, cats can purr to get what they want. Most of the time, Delgago said, the purring is a reflex; but purring can also be intentional. According to a 2009 study in the journal current biology (opens in a new tab)cats use a specific “purr of request” to beg for food or push humans out of bed. This purr is mixed with higher frequencies that sound a bit like a baby crying. “When humans hear cats purr loudly using a request purr,” Anderson said, “they see it as urgent.”
Although cats usually purr when they are happy; that is not always the case. Sometimes they purr when stressed, Delgado said.
“I had a cat that used to purr at the vet office, and my cat definitely didn’t like going to the vet!” Delgado said. “So that was kind of a stress response.”
Anderson has treated many injured and purring cats; she also believes that purring can be a coping mechanism, as it can help calm them down when they’re sick, scared, or dying.
One idea is that purring can help cats heal. A 2001 study in The Journal of the Acoustical Society of America (opens in a new tab) noted that cats purr at frequencies between 20 and 150 hertz, which are similar to the frequencies used in human treatments (opens in a new tab)for bone growth and muscle pain.
But there is no hard evidence to support or refute this idea, Delgado said. “There has never been a study of cat purrs to suggest that they have magical healing powers,” he said. “But it could be something comforting.”
So how can cat owners tell which purr is which? “You have to be a bit of a detective,” Delgado said. Depending on the context, a cat owner can make a good guess as to why their cat is purring.
If a cat is healthy, the next clue to what a purr means is body language, Delgado said. Does the cat look happy and relaxed? If so, the answer is probably, “Yes, your cat is enjoying this moment with you.”