WEBVTT - How (And Why) Do Cats Purr?

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<v Speaker 1>Welcome to brain Stuff from how Stuff Works. Hey, I'm

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<v Speaker 1>Christian Sagar and this is brain stuff. Let's get something

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<v Speaker 1>straight about cats right away from the beginning. Not all

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<v Speaker 1>cats can purr. In fact, there's two kinds of cats,

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<v Speaker 1>the ones that purr and the ones that roar. For instance,

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<v Speaker 1>none of the panther knee I subfamily of cats can

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<v Speaker 1>pur This includes lions, leopards, jaguars, and tigers, but boy

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<v Speaker 1>can they roar. The cats that can purr include our

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<v Speaker 1>common domestic cats, as well as big cats that can't roar,

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<v Speaker 1>like bob cats, cheetahs, lynxes, pumas, and wildcats. These are

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<v Speaker 1>the ones we care about, right because it feels like

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<v Speaker 1>they're sharing their contentment with us when they're happy, and

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<v Speaker 1>we're just playing fascinated with cats because well, you know

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<v Speaker 1>the Internet. But how did these non roaring cats actually

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<v Speaker 1>do the whole purring thing anyway? Well, the most accepted

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<v Speaker 1>idea is that a cat's brain signals the laryngeal muscles

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<v Speaker 1>in its voice box, so they vibrate. These muscles act

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<v Speaker 1>like a valve by opening and closing the glottis that's

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<v Speaker 1>the space between the vocal cords, and then allowing air

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<v Speaker 1>to flow past the cat's voice box. One reason we're

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<v Speaker 1>pretty sure this is how purring works is that cats

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<v Speaker 1>with laryngeal paralysis can't purr. What makes purring so distinctive

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<v Speaker 1>is that it works when cats are both inhaling and exhaling.

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<v Speaker 1>This is why it seems like they can just keep

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<v Speaker 1>purring forever. And while we have a pretty good idea

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<v Speaker 1>how purring works in the throat, scientists don't exactly a

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<v Speaker 1>dent agree on how cats initiate purring. Some believe it's

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<v Speaker 1>a voluntary act, initiated by their nervous system. This would

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<v Speaker 1>mean that cats only purr when they want to, but

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<v Speaker 1>other studies suggest that the pur signal comes from a

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<v Speaker 1>neural oscillator in the cat's brain. Still, another theory is

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<v Speaker 1>that purring is caused by the release of endorphins. When

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<v Speaker 1>cats experien it's either pleasure or pain. That's right. Cats

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<v Speaker 1>don't always purr when they're happy. Sure, we mostly hear

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<v Speaker 1>them do it when we're petting or feeding them and nursing.

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<v Speaker 1>Kittens pur to let their mothers know their well because

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<v Speaker 1>they can't me out and drink milk at the same time.

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<v Speaker 1>So purring is kind of a way for them to

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<v Speaker 1>bond with their mothers and say hey mommy, I'm I'm okay.

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<v Speaker 1>But purring communicates more than just happiness. Upset, injured, sick,

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<v Speaker 1>and even dying cats are known to purr. Female cats

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<v Speaker 1>sometimes per when they're delivering kittens. Animal behaviorists think that

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<v Speaker 1>these cats are purring under difficult circumstances because they're comforting themselves.

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<v Speaker 1>It's also possible that frightened cats per to communicate peaceful

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<v Speaker 1>intentions to signal that they won't attack. Older cats do

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<v Speaker 1>this sometimes when they approach younger cats to say hey you,

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<v Speaker 1>I'm friendly. There's another pretty awesome hypothesis about white cats purr.

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<v Speaker 1>The rapid opening and closing of their vocal cords creates

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<v Speaker 1>a sound somewhere between twenty and a hundred and fifty hurt.

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<v Speaker 1>These sound frequencies can both improve bone density and act

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<v Speaker 1>as a natural healing mechanism. There's evidence that shows purring

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<v Speaker 1>can repair bones, relieve pain, and even heal wounds. This

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<v Speaker 1>goes all the way back to an old veterinary legend

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<v Speaker 1>that if you place a disembodied cat in a room

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<v Speaker 1>with all of their body parts, they can reassemble their bones. Together.

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<v Speaker 1>So wait, if other cats can only roar and not

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<v Speaker 1>pur does that also mean they don't have these crazy

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<v Speaker 1>healing powers. Check out the brain stuff channel on YouTube,

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<v Speaker 1>and for more on this and thousands of other topics,

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<v Speaker 1>visit how stuff works dot com