Why and when do cats purr

The sound of a cat’s purr is one of the many enduring mysteries of our feline friends. Typically, we think of the purr as a sign of happiness. Then, on the way to the vet you may hear it — a little kitty motor. Nope, your cat isn’t broken, Dr. Lindsay Butzer, small animal veterinarian and general practitioner of PetMeds, says. A cat’s purr isn’t just to tell us how happy they are. So, why do cats purr?‍

How do cats purr?

Cats run their little motors by controlling the movement of the larynx (voice box) and diaphragms. The result is tension on the vocal cords when the cat breathes in, producing the beloved purr. 

“Purring is not an ability or skill that humans gave to, or brought about in, cats, though cats have likely expanded usage of purring in response to how they’ve seen humans react to purring over time,” Dr. Butzer explains.

What does it mean when a cat purrs?

The purr of a cat can indicate much more than happiness, Dr. Butzer says. Purring is an essential tool cats use to stay healthy. Some of the main reasons cats purr includes:

• Happiness: Used in cat-to-cat communication and cat-to-human communication, cats use the power of their purr to send happy vibrations to others.
• Healing: “Some studies indicate that the frequencies generated by the purr help stimulate bone and tendon healing,” Dr. Butzer says. Other frequencies of purr line up with therapeutic ranges for pain, and it’s presumed that purring helps strengthen the muscles and bones.
• Stress or pain: The sound of a purr doesn’t just bring happiness to humans. Purring releases feel-good chemicals in a cat’s brain, called endorphins. For this reason, Dr. Butzer says, a cat might purr when you least expect her to — like on the way to the vet or while giving birth. The endorphins help self-soothe and mask pain.
• Attention: Purring isn’t a response to human domestication, but cats are no strangers to using the power of the purr to grab and keep your attention.

If you’re wondering if your happy house cat is the only type of cat to purr, Dr. Butzer says feral, stray and even large, wild cats harness the power of the purr, too. 

“They probably don’t purr for the same reasons as domestic cats,” she says. “Their reasons for purring are likely to be more utilitarian and survival-based, such as to guide kittens or relieve pain and stress, rather than express contentment or guide the actions of a human.”

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When do kittens start purring?

Kittens begin purring (and responding to purrs) just days after being born. 

“Since kittens can’t see or hear, a mother’s purr is a way of sending vibrational messages to her kittens. They can feel the vibrations, guiding them to her so they can nurse,” Dr. Butzer says. In response, a kitten might purr to let mama know she would like mealtime to continue.

Why do cats purr when you pet them?

If you’re worried that your cat is purring while in pain or feeling anxious, look for other signs of discomfort such as vocalization, dilated pupils, ears back, tail flicking and a tight, drawn-in body posture. If you spot these signs, it might be time to chat with the vet or to remove the stressor. 

But for the most part, your cat likely purrs out of contentment when being pet. 

“If they’re purring in response to something that you’re doing, such as petting them, then they’re probably telling you to continue petting them,” Dr. Butzer says.

You can cuddle knowing full well your purring kitty is enjoying their time with you just as much as you are. 

The Dig, Fetch by The Dodo’s expert-backed editorial, answers all of the questions you forget to ask your vet or are too embarrassed to ask at the dog park. We help make sure you and your best friend have more good days, but we’re there on bad days, too. Fetch provides the most comprehensive pet insurance and is the only provider recommended by the #1 animal brand in the world, The Dodo.