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Science

Scientists Explain Feline Purring 40

Posted by timothy from the so-if-we-could-get-babies-to-purr? dept.
Manuka writes: "The Daily Telegraph has an article that tells us that scientists have discovered that purring in cats is actually a self-healing mechanism that strengthens their bones and lends weight to the extraordinary resilience of felines. Tigers lack this mechanism for some reason. They are also exploring the possibilities of replicating this mechanism in humans with 'sound treatment,' to help treat bone disorders." This article does not address how cats purr, though, and that seems like just as burning a question, nor does it explain how those low-freq sounds actually do achieve the benefits attributed to them.
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Scientists Explain Feline Purring More

Scientists Explain Feline Purring

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  • Tigers (Score:1)

    by Anonymous Coward

    Tigers lack this mechanism for some reason.

    Well, duh! Tigers get strong bones from all those bowls of Frosted Flakes they eat. They're grrrrrrrrreat!

  • Posted by thepanicofficer:

    "CATS: I SCRATCH YOU IN EYE YOU HAVE NO CHANCE TO SURVIVE MAKE YOUR TIME" oh hasn't this been completely played out already? i recently heard that someone hung an all your base banner from one of my university's parking garages... oh my.
  • Posted by Noble-Gas:

    This reminds me of a /. article from last month...?

    >> A State University of New York at Stonybrook researcher has invented a machine that estimulates bone growth in subjects by just having them stand on a vibrating platform. A sheep usin the gizmo 20 minutes a day had 20% denser bones after only a year

    http://slashdot.org/science/01/02/10/0327241.shtml [slashdot.org]

  • There have been some studies that showed that dog-owners have lower stress (no such correlation for other pets, e.g. cats).

    Maybe it's because they go for walks more often, or because they're less obsessive-compulsive about keeping their house clean and spotless since Spot will just screw everything up again.

    Whatever... you can cuddle with your purring cat on the sofa to "increase your bone mass" all you like, I'm going to go out in the sun and chase some squirrels with my dog! :>

  • How (Score:2)

    by Xunker ( 6905 )
    How they purr? I had it explained to me (from a PBS Special, IIRC), that the 'purring' noise is the result of bones/cartalige ridges (sp) vibrating togther in the larnyx.

    They went on to say that 'big cats' (tigers, lions, etc) CAN'T purr, because these bones/whatever in the throat have in fact evolved into the mechanisms responsible for roaring. House cats, as well, can't roar, but can (obviously) purr.

  • It's out of UHF:

    Raul: Today, we teach poodles how to fly!!

    -jdm

  • Now they need to figure out what makes an Octopussy purr.

    --
  • (re: title ... OK, not surprising, but I boggled at this quote :)
    Dr von Muggenthaler said that purring had to be advantageous to a cat to survive natural selection,

    That's at best contentious, and at worse misleadingly false. Not every trait that survives or is prevalent in a species needs to be advantageous. I'm as hard-core a Darwinian as you will find out there, but there are lots of reasons purring could have survived without being advantageous to cats. It could be linked to something that does something that does contribute to survival but is in and of itself of no advantage or even small detriment to survival. Or it could have been useful at some point in the past, and not any longer (who knows, primordial feline predators who have since gone extinct might have been confused by those frequencies).

    No sir, I don't like it when scientists make these sorts of errors.

  • Check out the straight dope [straightdope.com] on this...
  • Actually the reason cats survive falls has been studied separately has has to do with the overall physiology and the shape of the cat. It *also* has to do with how far they are falling. When cats fall they go into a 'trance' like state and actually change the way their body is positioned into more of a 'parachute' type of shape. Ever notice during a fall that cats legs tend to 'spread out' as if they're trying to catch the wind? Well, they are. However they need a few seconds to figure out rate of decent vs. distance to know how to absorb the impact. A fall of less than 9 feet is usually no problem. However a fall of 9 to 12 feet usually proves harmful (I don't *even* want to know *how* the people who did this study figured that out - or how many cats that took). Here's the interesting part: a fall of *more* than 12 feet is as survivable for them as the fall of *less* than 9 feet. This gives them time to make their 'parachute' and determine the best landing posture.

    They also found that falling into the mouth of a waiting dog proved harmful from *any* height. The results of this part of the study remained inconclusive but they think it might have had something to do with fear of -or some sort of allergy to - dog breath... ;-)
  • ...then why don't other animals with bones do it too?
    --
  • That "definition i quote" is the onestill in use ast the Bronx zoo as of a year ago, the San Francisco Zoological society as of 2 years ago, and every boo kI've ever read on the subject hta was written by a DVm or someoen with similar academic crednetials. (And I read a lot of them. The cats are a great interest of mine.)

    Can you show me a webstie with soemd egree of authority that says different? (Authority is key, I can show you a website thats says ANYTHING and websites often quote each other. According to most of the web Weird AL wrote "What if god smoked Canabis" which is completel;y wrong.)

    I note though that evben yo uadmitted "iots not quite the same thing" which is to say you uadmitted that Great Cats DON'T purr. They do something else which you have arbitrarily over-loaded the term purr onto.

    The fact of the matter, for anyone who is interested in real science, is cats can leap off of roofs because the have a much smaller body-mass to surface area ratio then huamns and thus have a lower terminal verlocity. Thsi is basic high-school physcis.

    A mouse, which doesnt purr, can fall off the top of the empire state building and walk away.

    I like someoen elses suggestion, go strap 5 cats on your body and jump off out a thrid story window if you buy this reseracher's nonsense. :)

  • I'd give you I may be mixing up growl and roar. Its been awhile (abt a year) since i last looked at these definitions.

    Then again I'n not publishing on the topic or I'd be a LOT mor carefuly to get the details correct...

  • Great Cats are your lions, tigers and such.

    'nuff said
  • That small cats purr in response to **any** strong emotional state.

    Which explains an awful lot better your "cats purr when injured" factoid as WELL as why they purr when stroked.

    Ofcourse thats typocal psuedo-sciecne logic. "Cats purr when injurered therefor purring must be caused by injury." Thats called confusing a correlation with a causality.
  • This IS a joke, right???

    Its not just Tigers, it sall great Cats that don't purr. Ist the construction of the voice box. Great Cats can growl but not purr, small cats can purr but not truely growl. in afct, this is the DEFINITION of Great Cat and small cat.

    Hard to take any supposed 'resarcher" seriously who didn't even know the bilogical definitiosn of his subject material.

    This belongs on Whitley's World, not Slashdot.

    (If you are INTO new-age total BS psuedo-science you might want to try www.whitleysworld.com)
  • Yeah, that's a great idea. I'm going to go tape some cats to my head right now!


    CATS: I SCRATCH YOU IN EYE YOU HAVE NO CHANCE TO SURVIVE MAKE YOUR TIME

  • Strap several live cats to your body then jump off a building. You should recover from any incidental broken bones in a day or so. Well, provided you don't die of blood loss.

  • Well According to an article previously posted on slashdot Stimulating Bone Growth In Astronauts [slashdot.org] "A State University of New York at Stonybrook researcher has invented a machine that stimulates bone growth in subjects by just having them stand on a vibrating platform." Since this device is shown to increase bone growth from the use of an external device emmiting a frequency within the 20-50Hz range, then wouldn't it be possible that a cat's purring, which is within the same frequency range, could have a similar effect on a person as that found by using this device?
  • This article leads me to wonder if they have considered studying people who are long time owners of cats to see if they have any significant increase in bone mass as compared to the average person. It would seem to me that if you were to regularly hold a cat while it was purring then you would be likely to recieve some of the benefits of the purring as well (at least in the region of your body that was in contact with the cat).
  • This, they say, explains why cats survive falls from high buildings and why they are said to have "nine lives". Exposure to similar sound frequencies is known to improve bone density in humans.

    This, they say, explains why mosh-divers survive leaps into crowds of drunken rock fans.
  • I like cats and all, but I found the mental picture I formed while reading this quite funny: Men dressed in white lab coats conducting an official study by throwing cats out windows to see if they'd survive, with another man with a clipboard and white lab coat standing on the ground tallying the results.

    This reminds me of a WWII story. Seems someone got the bright idea that, since cats hate water, they'd make good pilots for anti-ship bombs. The thinking (if that's what you could call it) was that you'd stick a cat in a bomb with some controls that it was trained to use, and it would guide the bomb away from water and toward the ship. They had to drop a cat in harness a few times to prove that this was one of the dumbest ideas anyone ever had.

  • Maybe I've just seen one too many cheezy martial arts movies, but a quick search with Google showed that there apparently really are some religious groups out there who hum low-frequency sounds while meditating (there are tons of really wacked-out new agea types clouding the search results though ... anyone here an expert on ancient Asian or Indian religions?).
  • Its not just Tigers, it sall great Cats that don't purr. Ist the construction of the voice box. Great Cats can growl but not purr, small cats can purr but not truely growl. in afct, this is the DEFINITION of Great Cat and small cat.
    That "definition" you quote was formulated in 1916 and is not universally followed. Lions and many other big cats do purr, although they are only able to purr as they exhale so it's not quite the same as with smaller cats.

    Here are a few pages with details:
    wav of Cheetah purr, [iprimus.com.au]
    Big cats, [iprimus.com.au]
    Lion, [lionresearch.org]
    Puma. [tamu.edu]

    As for the research, it's a well known fact that injured cats purr (see, e.g. Encyclopaedia Britannica) so it's hardly suprising that it might have some beneficial effect. Here's a link to the original article this story is on. [animalvoice.com]

  • Strap several live cats to your body then jump off a building. Or better yet, try the cat-jam anti-gravitational device.

    As anyone knows, whenever you drop a slice of bread with jam and/or jelly spread on one side, that side will always fall face-down to the floor. If you take a cat and drop it, it'll always fall feet down.

    So just strap a slice of bread with jam over the back of a cat, and then drop the cat. What side'll land on the floor? Well none! The cat'll float in midair, since Nature's undecided on which side to drop first.

    Naturally, that's how UFOs work. And that also explains the buzzing heard around them, which is obviously just several hundred cats purring at the same time.

    My apologies to the original version of this story, which appeared somewhere in the mid-90's on the Oracularities.
  • It's the cat's meow! Is now obsolete. From know on the saying will get written and said as, It's the cat's purr!

    Somehow it doesn't have that "ring" like the old saying had.
  • Great Cats can growl but not purr, small cats can purr but not truely growl

    Small cats can't growl? You haven't met my cats apparently...

  • I liked this quote (Score:4)

    by HiNote ( 238314 ) on Monday March 19, 2001 @05:29AM (#354436)
    One recent study, published in The Journal of the American Veterinary Medical Association, found that out of 132 cats that fell an average of 5.5 storeys, 90 per cent survived, including one that fell 45 storeys.

    I like cats and all, but I found the mental picture I formed while reading this quite funny: Men dressed in white lab coats conducting an official study by throwing cats out windows to see if they'd survive, with another man with a clipboard and white lab coat standing on the ground tallying the results.
  • Amen to that! Last night I clipped Cat's toenails. Kittys can MOST DEFINATELY growl!
  • Nor do I have documentation, but I recall reading an article that said that purring was a method that cats used to communicate to Mom that they were ok while nursing.

  • Re:I liked this quote (Score:3)

    by sporktoast ( 246027 ) on Monday March 19, 2001 @08:04AM (#354439) Homepage

    I read somewhere a while ago about injury rates for cats falling from various heights.

    Apparently, severity & likelihood of injury climb upward as the height goes up, as you might expect. But then somewhere up several stories, the injury rate and severity suddenly dropped significantly, then began climbing again, but more slowly. After a bit if research, someone discovered an explanation.

    Cats reflexively turn to land on their feet as they fall. As you get above a couple of storeys, this becomes more of a liability. The accelerated velocity combined with the tense, standing position increases the likelihood of broken limbs. If the height is above that several-storey mark, the cat gets pretty much to terminal velocity for its weight/wind resistence. At that point, the cat relaxes and spreads it's legs out. The increase in drag actually slows the cat down a bit. And the relaxed posture also spreads out the impact area. Result: fewer and less sever injuries.

  • Would you believe it has already been done (snicker>? Well, consider the source of this article [improb.com] at The Annals of Impropable Research [improb.com]. They dropped a cat named Esther 100 times each from six various heights. It's funny stuff!

    There is still a lot of speculation about why cats purr. Mine usually purr when I pet or feed them. They will also purr while growling/hissing/meowing, all at the same time, if they get hold of any skinks (similar to PCP in humans...)

    Felis Domesticus as a species is pretty bad-assed. Cats are considered the best predator pound-for-pound on the planet. Yet they spend 2/3 of their day sleeping. Cats have basically enslaved the most advanced species on the planet. They don't need an opposible thumb because we can open the cat food for them. After we're done wiping ourselves out, cats will eventually become the dominant species on Earth.



    If you love God, burn a church!
  • At no point in the article do they quote one of the researchers saying that great cats purr. I'd say that it's the journalist that screwed up. Basically any technical article written by a journalist is going to be wrong on a few (perhaps major) points. They try to write summaries of research that has taken sometimes decades of work to comprehend, but they only spend a few days researching the topic.
  • A long time ago on some mainstream TV news show (I forget which), I heard that humming and such noises that cause mild vibrations in humans which have a similar healing mechanism for the lungs and headaches. I have no idea if this is true but it's an interesting correlation. Has anyone else heard this or is this some weird New Age hogwash?

    Maybe the cats have had it right all along, lol.

  • Well, Hindi (practitioners of Hindu) use mantras (a series of words, repeated as rhythmically as possible) in meditation to perform various effects, one of which is healing. While Hindi believe that this is because they are balancing the flow of life through their bodies, they have also noted that the vibrations seem to be crucial in distributing the energies. So then the short answer to your question is yes, some humans have indeed clued in to this. The Hindi have been doing this since the beginning of their culture, some thousands of years ago.
  • I thought cats just weren't smart enough to bark.

  • Actually, Cheetahs are considered the largest of the small cats, specifically because they can purr but not roar. Using them as an argument in the purr discussion is rather pointless.

    I don't know where this whole "growl" thing came from. I learned that the big cats can roar, and small cats purr. Anyone who believes a small cat can't growl hasn't owned one (or hasn't seen one really pissed off).

  • Am I the only one who noticed that under the photo of the two kitties, the caption regarding wounded cats begins with "None lives"?

    It took me a moment to figure out why none of the photographed cats would survive, and then the typo finally dawned on me.

  • Assuming cats purr to heal their bones. Then why do they purr when you pet them? Is it some sort of reaction that corresponds with touch on the bone it self, or an emotional response?

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