Why Do Cats Purr?
By Dr. Carly I. O'Malley March 21, 2019
One of the best parts of owning a cat is hearing their purrs. The sound is comforting to cat parents because it typically signifies that our cat is happy and content. But there is more to a purr than that. Purrs can signal different emotional states and have a positive physiological effect on humans. In this article, we will answer some common questions about cat purring to help you learn a little more about our feline friends.
Why Do Cats Purr?
The primary role of purring is as a mode of communication with other cats or with people. Mother cats will purr while giving birth and will use purring to communicate with her kittens after they are born. The kittens can feel the vibrations from their mother, and then they are able to find her for nursing and warmth. Purring is also one of the first sounds that kittens can produce. They will purr during nursing, which may communicate to the mother that they are getting milk or that they would like to keep nursing (Brown & Bradshaw 2013; Hart & Hart, 2013).
Cats purr with humans as well. While many people think that purring is simply a sign of pleasure or contentment, cats have adapted to use purring in a variety of contexts. Cats may even have different purrs for different things, like one for when they are happy on your lap and one for when they want food or attention from you. It is thought that cats use purring as a way of getting attention from their owners, which may be why cats also purr in stressful or painful situations (Brown & Bradshaw, 2013; Hart & Hart, 2013).
In addition to using purring as a means of communication, it is believed that purring also promotes pain management and wound healing. This may explain why it occurs during labor. Purring during labor might help promote muscle and bone growth in the kittens. Purring occurs at a frequency of 25 Hz, which is the frequency used by physical therapists to help with pain and other ailments. Therefore, cats may purr to self-soothe in stressful situations because of its healing powers (Hart & Hart, 2013). Cats are extremely perceptive animals, and you may notice that if you are stressed or in pain your cat will come lay on you and start to purr. That may be their way of helping you heal!
How Do Cats Purr?
Purring is often described as a soft rumbling sound that also causes vibrations from the cat itself. Owners can usually hear and/or feel the purring coming from their cat, with some cats purring louder than others (Frazer-Sissom et al., 1991). Cats often purr while they are breathing or when making other vocalizations. It has mystified scientists for years on how cats physically make this sound. Recent evidence has shown that purring is not the same as typical vocalizations that cats make. Cats can purr while they are inhaling and exhaling, whereas vocalizations can only be made when cats exhale. It is thought that purring occurs due to air buildup and release of pressure created by the opening and closing of the glottis. This causes a separation in the vocal folds and vibration of the laryngeal muscles as air flows in and out (Frazer-Sissom et al., 1991; Hart & Hart, 2013).
Do Any Other Felines Purr?
Yes! Our domestic cats are not the only purring species. Many other members of the Felidae group also purr. Some scientists classify felids into two different groups: the purring cats and the non-purring, roaring cats. Non-purring, roaring cats include lions, tigers, jaguars, and leopards. The roaring ability is a result of a hyoid that is incompletely ossified. Snow leopards also have this feature, but they have retained the ability to purr (Eklund et al., 2010). Cougars and cheetahs can also purr, along with smaller cats such as bobcats, lynx, servals, ocelots, and wildcats.
As a cat owner, it is important to understand the different ways in which your cat communicates with you. Purring is an important one that many cat parents do not quite understand or may have misconceptions about. We hope that this article has provided you with useful knowledge on why and how your cat purrs. Most importantly, understand that cats can purr in different contexts, whether they are content, stressed, or in pain. For example, some cats purr while they are at the vet, which might be a sign that they are stressed, even if they are otherwise being friendly and outgoing. Do not be afraid of providing your cat some pets and snuggles to let them know that you are there and that they are safe. If your cat is suddenly purring more than normal, it could be an indication that your cat is not feeling well and that you may want to visit the veterinarian for a checkup. Lastly, if your cat comes over to you while you are watching TV, curls up on your lap, and purrs away, then enjoy the bond you have with them (and the healing powers of purrs!).
Brown, S.L., and J.W.S. Bradshaw. 2013 Communication in the domestic cat: within- and between-species. In D. Turner and P. Bateson (Eds), The Domestic Cat: The Biology of its Behaviour (p. 201-212). Cambridge: Cambridge University Press.
Eklund, R., Peters, G., and E.D. Duthie. 2010. An acoustic analysis of purring in the cheetah (Acinonyx jubatus) and in the domestic cat (Felis catus). In Fonetik 2010, Lund University, 2–4 June 2010, Lund, Sweden (pp. 17-22). Mediatryck.
Hart, B., and L. Hart. 2013. Normal and problematic reproductive behaviour in the domestic cat. In D. Turner and P. Bateson (Eds), The Domestic Cat: The Biology of its Behaviour (p. 201-212). Cambridge: Cambridge University Press.
Frazer-Sissom, D.E., Rice, D.A., and G. Peters. 1991. How cats purr. Journal of Zoology 223, 67-78.