Welcome to brain Stuff from how Stuff Works. Hey, I'm Christian Sagar and this is brain stuff. Let's get something straight about cats right away from the beginning. Not all cats can purr. In fact, there's two kinds of cats, the ones that purr and the ones that roar. For instance, none of the panther knee I subfamily of cats can pur This includes lions, leopards, jaguars, and tigers, but boy
can they roar. The cats that can purr include our common domestic cats, as well as big cats that can't roar, like bob cats, cheetahs, lynxes, pumas, and wildcats. These are the ones we care about, right because it feels like they're sharing their contentment with us when they're happy, and we're just playing fascinated with cats because well, you know the Internet. But how did these non roaring cats actually
do the whole purring thing anyway? Well, the most accepted idea is that a cat's brain signals the laryngeal muscles in its voice box, so they vibrate. These muscles act like a valve by opening and closing the glottis that's the space between the vocal cords, and then allowing air to flow past the cat's voice box. One reason we're pretty sure this is how purring works is that cats
with laryngeal paralysis can't purr. What makes purring so distinctive is that it works when cats are both inhaling and exhaling. This is why it seems like they can just keep purring forever. And while we have a pretty good idea how purring works in the throat, scientists don't exactly a dent agree on how cats initiate purring. Some believe it's
a voluntary act, initiated by their nervous system. This would mean that cats only purr when they want to, but other studies suggest that the pur signal comes from a neural oscillator in the cat's brain. Still, another theory is that purring is caused by the release of endorphins. When cats experien it's either pleasure or pain. That's right. Cats don't always purr when they're happy. Sure, we mostly hear them do it when we're petting or feeding them and nursing.
Kittens pur to let their mothers know their well because they can't me out and drink milk at the same time. So purring is kind of a way for them to bond with their mothers and say hey mommy, I'm I'm okay. But purring communicates more than just happiness. Upset, injured, sick, and even dying cats are known to purr. Female cats sometimes per when they're delivering kittens. Animal behaviorists think that these cats are purring under difficult circumstances because they're comforting themselves.
It's also possible that frightened cats per to communicate peaceful intentions to signal that they won't attack. Older cats do this sometimes when they approach younger cats to say hey you, I'm friendly. There's another pretty awesome hypothesis about white cats purr. The rapid opening and closing of their vocal cords creates a sound somewhere between twenty and a hundred and fifty hurt. These sound frequencies can both improve bone density and act
as a natural healing mechanism. There's evidence that shows purring can repair bones, relieve pain, and even heal wounds. This goes all the way back to an old veterinary legend that if you place a disembodied cat in a room with all of their body parts, they can reassemble their bones. Together. So wait, if other cats can only roar and not pur does that also mean they don't have these crazy
healing powers. Check out the brain stuff channel on YouTube, and for more on this and thousands of other topics, visit how stuff works dot com