Why and how do cats purr?

    No one knows for sure why a domestic cat purrs, but many people interpret the sound as one of contentment. Our understanding of how a domestic cat purrs is becoming more complete; most scientists agree that the larynx (voice box), laryngeal muscles, and a neural oscillator are involved.

Kittens learn how to purr when they are a couple of days old. Veterinarians suggest that this purring tells ‘Mom’ that “I am okay” and that “I am here.” It also indicates a bonding mechanism between kitten and mother.

As the kitten grows into adulthood, purring continues. Many suggest a cat purrs from contentment and pleasure. But a cat also purrs when it is injured and in pain. Dr. Elizabeth Von Muggenthaler has suggested that the purr, with its low frequency vibrations, is a “natural healing mechanism.” Purring may be linked to the strengthening and repairing of bones, relief of pain, and wound healing (See Web link to Felid purr: a healing mechanism).

Purring is a unique vocal feature in the domestic cat. However, other species in the Felidae family also purr: Bobcat, Cheetah, Eurasian Lynx, Puma, and Wild Cat (Complete list in Peters, 2002). Although some big cats like lions exhibit a purr-like sound, studies show that the Patherinae subfamily: Lion, Leopard, Jaguar, Tiger, Snow Leopard, and Clouded Leopard do not exhibit true purring (Peters, 2002).”

What makes the purr distinctive from other cat vocalizations is that it is produced during the entire respiratory cycle (inhaling and exhaling). Other vocalizations such as the “meow” are limited to the expiration of the breath.

It was once thought that the purr was produced from blood surging through the inferior vena cava, but as research continues it seems that the intrinsic (internal) laryngeal muscles are the likely source for the purr. Moreover, there is an absence of purring in a cat with laryngeal paralysis. The laryngeal muscles are responsible for the opening and closing of the glottis (space between the vocal chords), which results in a separation of the vocal chords, and thus the purr sound. Studies have shown, that the movement of the laryngeal muscles is signaled from a unique “neural oscillator” (Frazer-Sisson, Rice, and Peters, 1991 & Remmers and Gautier, 1972) in the cat’s brain.

Related Web Sites

Animal Planet: Cat guide - The Cat Guide provides information on many cat questions such as “Why do cats land on their feet after a fall?” The Web site also provides information about cat care, choosing a cat, training a cat, and cat safety. Pet Tails: Why cats purr? - A brief article by Susan Daffron about Why cats purr. Cornell Feline Health Center - “The Feline Health Center is a veterinary medical specialty center devoted to improving the health and well-being of cats everywhere” Of special interest is the Health Information. Felid purr: A Healing Mechanism - Elizabeth Von Muggenthaler presented this paper at the 2001, 142nd annual Acoustical Society of America, American Institute of Physics, International Conference. It discusses the possibility that purring is an evolutionary healing mechanism in felines. Google Directory > Cats - The Google Directory for Cats lists Web sites on topics related to cats such as cat breeds and cat behavior. Yahoo Cats - Yahoo’s Cats page contains cat articles, cat tip of the day, and much more

Further Reading

Beaver, Bonnie V. Feline behavior: a guide for veterinarians. 2nd ed. St. Louis, MO, Saunders, c2003. 349 p. Case, Linda. The cat: its behavior, nutrition, & health. Ames, Iowa, Iowa State Press, c2003. 392 p. De Lanerolle, Nihal C. and Frederick F. Lang. Functional neural pathways for vocalization in the domestic cat. In Physiological control of mammalian vocalization. Edited by John D. Newman. Plenum Press, New York, London, c1988: 21-41 Dibra, Bash and Elizabeth Randolph. Cats speak: how to learn it, speak it, and use it to have a happy, healthy, well-mannered cat. New York, Putnams’s, c2001. 237 p. The domestic cat: the biology of its behaviour. Edited by Dennis C. Turner and Patrick Bateson. 2nd edition. Cambridge, UK, New York, Cambridge University Press, 2000. 244 p. Frazer-Sissom, Dawn E., D.A. Rice, and G. Peters. How cats purr. Journal of zoology: proceedings Zoological Society of London, v. 223, January 1991: 67-78.. Hickey, Georgina. The power of purring. Nature Australia, v.27, Winter 2002: 16- 17. Holub, Joan. Why do cats meow? New York, Dial Books for Young Readers, c2001. 46 p. (juvenile). Moelk, Mildred. Vocalizing in the house cat. American journal of psychology, v. 57, 1944: 184-205. Peters, G. Purring and similar vocalizations in mammals. Mammal Review, v32, Dec. 2002: 245-271. Purr-tence and physiology. Editorial. Lancet, v. 339, June 27, 1992: 1578. Remmers, J.E. and H. Gautier. Neural and mechanical mechanisms of feline purring. Respiration Physiology, v. 16, December 1972: 351- 361. Tabor, Roger. Understanding cats: their history, nature, and behavior. Pleasantville, New York, Reader’s Digest, 1997. 144 p.

For more print resources...
Search on "cats," "cats behavior," "cats physiology," "cat family," "felis," and "felidae." in the Library of Congress Online Catalog.

A cat will often purr when being stroked and
petted.

Cat and her kittens. Canyon County, Idaho.
Prints & Photographs Division, Library of
Congress.

Catsup - Man squirting milk from cow into
mouth of a cat. Prints & Photographs
Division, Library of Congress.

Photo: Lynx kitten. From the U.S.
Fish & Wildlife Service Web site.

Photo: Cheetah. From the
Yellowstone Digital Slide File,
National Park Service.

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