# Cat's Purring? **URL:** \ **Category:** Factual Questions\ **Created:** [May 27, 2006, 5:35pm UTC](https://boards.straightdope.com/t/cats-purring/358465 "2006-05-27T17:35:10Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![turlington88](https://avatars.discourse-cdn.com/v4/letter/t/e5b9ba/32.png) [@turlington88](https://boards.straightdope.com/u/turlington88)\ **Post date:** [May 27, 2006, 5:35pm UTC](https://boards.straightdope.com/t/cats-purring/358465/1 "2006-05-27T17:35:10Z")
Hello there, I have been informed that no one knows the reason why cats purr, so first of all, is this true? And secondly, is it true that the vibrations/oscillations of a cat’s purr is equal or similar to that of an ultra sound machine, and because of this, cats do not suffer from muscular problems? ---
**Author:** ![worrywort](https://avatars.discourse-cdn.com/v4/letter/w/ebca7d/32.png) [@worrywort](https://boards.straightdope.com/u/worrywort)\ **Post date:** [May 27, 2006, 5:43pm UTC](https://boards.straightdope.com/t/cats-purring/358465/2 "2006-05-27T17:43:07Z")
[quote] And so it is with cats purring. We cannot purr, so we are interested in how cats can do it. It turns out that domestic cats, some wild cats like pumas and mountain lions (in general, any big cat that cannot roar) and even raccoons are all able to purr. Humans happen to smile and laugh when they are happy, and dogs wag their tails. So it is not unusual for an animal to have a physical reaction to happiness. Cats show happiness by purring. They may also purr when startled or upset. It turns out that cats have special wiring! The wiring travels from the brain to the muscles in the voice box, and this wiring is able to vibrate the muscles so that they act as a valve for air flowing past the voice box. The muscles work both during inhalation and exhalation, which creates the impression that cats can purr continuously. The air passes through the valve, which opens and closes rapidly to create the purring sound.[/qoute] ---
**Author:** ![worrywort](https://avatars.discourse-cdn.com/v4/letter/w/ebca7d/32.png) [@worrywort](https://boards.straightdope.com/u/worrywort)\ **Post date:** [May 27, 2006, 5:44pm UTC](https://boards.straightdope.com/t/cats-purring/358465/3 "2006-05-27T17:44:21Z")
Hey! Why didn’t that work like i wanted it to? Sorry… ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [May 27, 2006, 5:49pm UTC](https://boards.straightdope.com/t/cats-purring/358465/4 "2006-05-27T17:49:00Z")
The Purrfect Master Speaks: [Why do cats purr?](http://www.straightdope.com/classics/a1_007.html) ---
**Author:** ![Eve](https://avatars.discourse-cdn.com/v4/letter/e/9e8a1a/32.png) [@Eve](https://boards.straightdope.com/u/Eve)\ **Post date:** [May 27, 2006, 6:15pm UTC](https://boards.straightdope.com/t/cats-purring/358465/5 "2006-05-27T18:15:19Z")
> [@](#): > > Cats don’t purr just when they’re feeling chipper–they also purr when they’re frightened or badly hurt. Not to second-guess **Cecil** , but I have been around cats all my life, and have _never_ heard one purr when “frightened or badly hurt.” ---
**Author:** ![robcaro](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@robcaro](https://boards.straightdope.com/u/robcaro)\ **Post date:** [May 27, 2006, 6:37pm UTC](https://boards.straightdope.com/t/cats-purring/358465/6 "2006-05-27T18:37:45Z")
> [@worrywort](#): > > Hey! Why didn’t that work like i wanted it to? > Sorry… Because your [/qoute] was misspelled. ---
**Author:** ![worrywort](https://avatars.discourse-cdn.com/v4/letter/w/ebca7d/32.png) [@worrywort](https://boards.straightdope.com/u/worrywort)\ **Post date:** [May 27, 2006, 6:45pm UTC](https://boards.straightdope.com/t/cats-purring/358465/7 "2006-05-27T18:45:13Z")
> [@robcaro](#): > > Because your [/qoute] was misspelled. Haha, yeah :smack: I also meant to say that that quote came from: > **[How do cats purr?](https://animals.howstuffworks.com/pets/question394.htm)** > > Purring is how cats express happiness. Rather than manipulating facial muscles like humans, cats purr as a physical reaction to happiness. How exactly do cats make that purring noise? Find out the answer to that question in this article. Cecil’s answer was much more in depth anyway. ---
**Author:** ![jjimm](https://avatars.discourse-cdn.com/v4/letter/j/ba8739/32.png) [@jjimm](https://boards.straightdope.com/u/jjimm)\ **Post date:** [May 27, 2006, 6:57pm UTC](https://boards.straightdope.com/t/cats-purring/358465/8 "2006-05-27T18:57:00Z")
> [@Eve](#): > > Not to second-guess **Cecil** , but I have been around cats all my life, and have _never_ heard one purr when “frightened or badly hurt.” I have: my first cat when she got the blow to the head that eventually killed her, and my present cat when she was a kitten and my dad stepped on her. ---
**Author:** ![Hilarity\_N.Suze](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hilarity_n.suze/32/6223_2.png) [@Hilarity\_N.Suze](https://boards.straightdope.com/u/Hilarity_N.Suze)\ **Post date:** [May 27, 2006, 7:17pm UTC](https://boards.straightdope.com/t/cats-purring/358465/9 "2006-05-27T19:17:25Z")
> [@Eve](#): > > Not to second-guess **Cecil** , but I have been around cats all my life, and have _never_ heard one purr when “frightened or badly hurt.” Not to say that Cecil is right about anything involving cats, but a small queen belonging to my college roommate purred throughout the duration of delivering eight good-sized kittens, which took awhile and couldn’t have been comfortable. ---
**Author:** ![SnakesCatLady](https://avatars.discourse-cdn.com/v4/letter/s/4af34b/32.png) [@SnakesCatLady](https://boards.straightdope.com/u/SnakesCatLady)\ **Post date:** [May 27, 2006, 7:24pm UTC](https://boards.straightdope.com/t/cats-purring/358465/10 "2006-05-27T19:24:12Z")
> [@Eve](#): > > Not to second-guess **Cecil** , but I have been around cats all my life, and have _never_ heard one purr when “frightened or badly hurt.” Working for a vet I have had the unfortunate duty to be around several cats who were badly hurt, and some of them did purr. Every cat I have been around while having kittens has purred during delivery. As far as the frightened part, as a cat trapper I have been responsible for frightening many cats, and I have never heard one purr. I have had them cuss me (you can tell when you’re being cussed no matter what language it’s in) and I have had tomcats pee on me, but I have never heard one purr while frightened. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [May 27, 2006, 8:36pm UTC](https://boards.straightdope.com/t/cats-purring/358465/11 "2006-05-27T20:36:51Z")
Wish I knew what it was about some kitties who make a trilling warble instead of a purr. One of the brood queens who hangs out in Catville does this, and some of her babies exhibit the same voice. ---
**Author:** ![Guinastasia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guinastasia/32/5751_2.png) [@Guinastasia](https://boards.straightdope.com/u/Guinastasia)\ **Post date:** [May 27, 2006, 8:59pm UTC](https://boards.straightdope.com/t/cats-purring/358465/12 "2006-05-27T20:59:08Z")
> [@Eve](#): > > Not to second-guess **Cecil** , but I have been around cats all my life, and have _never_ heard one purr when “frightened or badly hurt.” I have. Noel purrs when she gets scared. Whenever we take her to the vet’s they have a heard time taking her temp because she purrs so hard. ---
**Author:** ![Guinastasia](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guinastasia/32/5751_2.png) [@Guinastasia](https://boards.straightdope.com/u/Guinastasia)\ **Post date:** [May 27, 2006, 9:02pm UTC](https://boards.straightdope.com/t/cats-purring/358465/13 "2006-05-27T21:02:16Z")
> [@Guinastasia](#): > > I have. Noel purrs when she gets scared. Whenever we take her to the vet’s they have a heard time taking her temp because she purrs so hard. Uh, make that “they have a hard time GETTING HER HEARTBEAT” rather than “taking her temp.” :smack: ---
**Author:** ![jayjay](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jayjay/32/6765_2.png) [@jayjay](https://boards.straightdope.com/u/jayjay)\ **Post date:** [May 27, 2006, 9:21pm UTC](https://boards.straightdope.com/t/cats-purring/358465/14 "2006-05-27T21:21:28Z")
> [@Guinastasia](#): > > Uh, make that “they have a hard time GETTING HER HEARTBEAT” rather than “taking her temp.” > > :smack: I was going to say that’s _some_ purr if it makes her vibrate so hard they can’t get the thermometer in back there… ---
**Author:** ![drhess](https://avatars.discourse-cdn.com/v4/letter/d/94ad74/32.png) [@drhess](https://boards.straightdope.com/u/drhess)\ **Post date:** [May 27, 2006, 9:35pm UTC](https://boards.straightdope.com/t/cats-purring/358465/15 "2006-05-27T21:35:37Z")
My cat purrs while he’s exploring new parts of the condo building. I think it’s a way to keep up a bit of audible contact in an tense situation with his cat posse …er…well, with me in his case. ---
**Author:** ![xbuckeye](https://avatars.discourse-cdn.com/v4/letter/x/9e8a1a/32.png) [@xbuckeye](https://boards.straightdope.com/u/xbuckeye)\ **Post date:** [May 27, 2006, 10:02pm UTC](https://boards.straightdope.com/t/cats-purring/358465/16 "2006-05-27T22:02:22Z")
I think that the purr when scared thing is a “don’t hurt me I’m cute” reaction from my cat. She purrs when she’s about to catch hell for doing something BAD and usually rolls over into a submissive position. Fortunately, she’s never been hurt badly, but I’ve seen some cats hurt very badly still purr. In the vet clinic, it is often a life-preserver as even the hard-heartedest vet can’t euth a cat that is purring. I had a vet recap the syringe after wiping down the cat’s leg with alcohol and having me hold off the vein. The syringe was literally pressed against her skin, and he stopped because she was purring to beat the band. Another cat had an arrow clear through her leg and was not only purring, but was rolling as much as a cat with an arrow through its leg can. ---
**Author:** ![KP](https://avatars.discourse-cdn.com/v4/letter/k/a9adbd/32.png) [@KP](https://boards.straightdope.com/u/KP)\ **Post date:** [May 31, 2006, 7:25pm UTC](https://boards.straightdope.com/t/cats-purring/358465/17 "2006-05-31T19:25:06Z")
“no one knows why cats purr”? I daresay most of us have a pretty good idea what will and will not make most cats purr. Why they make that specific sound? Well, I’m not sure theyre is a reason. It’s just a sound they _can_ make, and it works. Why does “party” mean party? (BTW, cats aren’t the only animals that purr) While I can’t say I’ve ever fed a cat’s purr into a spectruma analyzer, it is generally a low frequency sound, and ultrasound is very high frequency. If a cat purred in the ultrasonic range, you wouldn’t be able to hear them. On the other hand, a _lot_ of human gear (e.g. televisions, brake pads, the inaudible IF of radio recievers, etc.) bathe us in high frequency sounds, which _are_ in the ultrasonic range. We just don’t notice because we can’t hear them. ---
**Author:** ![Santos\_L\_Halper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/santos_l_halper/32/1_2.png) [@Santos\_L\_Halper](https://boards.straightdope.com/u/Santos_L_Halper)\ **Post date:** [May 31, 2006, 7:30pm UTC](https://boards.straightdope.com/t/cats-purring/358465/18 "2006-05-31T19:30:19Z")
Here’s a [recent discussion](http://boards.straightdope.com/sdmb/showthread.php?t=373397) that should offer some info. Oh wait, you started that one too… :dubious: ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [May 31, 2006, 7:41pm UTC](https://boards.straightdope.com/t/cats-purring/358465/19 "2006-05-31T19:41:31Z")
> [@turlington88](#): > > Secondly, is it also true that cats purr at the same, or relatively similar frequencies to that of an ultra-sound machine? The frequency of a cat’s purr, about 26 Hertz, is about the same as an idling diesel engine. It’s definitely not similar to an ultrasound machine- 26 Hertz is near the low end of the range of human hearing. Ultrasound is sound above the high end of the range of human hearing- 20,000 Hertz or higher. > [@](#): > > This may account for why cats do not have muscle problems, and their extraordinary jumping talent. 😕 Even if cats did purr ultrasonically, what would that have to do with muscle problems or jumping? ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [May 31, 2006, 8:29pm UTC](https://boards.straightdope.com/t/cats-purring/358465/20 "2006-05-31T20:29:28Z")
Cats are a Slinky covered with Jello. They don’t have muscles, just something in there that stretches and bounces. How else could a cat fall from 85 feet from a tree and survive? (CNN) I think that there is one big cat brain, (someplace no one dares to go) controlling all kitty cats. For what reason, nobody knows. Be afraid. :eek: [Next page](https://boards.straightdope.com/t/cats-purring/358465.md?page=2)