Do Cats Purr

Hi, I'm Cristen from Stuff Mom Never Told You,

and let's get something straight about cats

right from the beginning.

Not all cats purr.

In fact, there are two kinds of cats,

the ones that purr

(cat purrs)

and the ones that roar.

(lion roars)

For instance, none of the Pantherinae subfamily

of cats can purr.

And this includes lions, leopards, jaguars and tigers.

But boy, can they roar.

Now the cats that can purr include our domestic common cats

as well as big cats that can't roar,

like bobcats, cheetahs, lynxes, pumas and wildcats.

And 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 are just plain fascinated with cats

because I mean, you know, the internet.

But how do these non-roaring cats

actually do the whole purring thing anyway?

Well, the most accepted idea is that a cat's brain signals

its laryngeal muscles in its voice box so that they vibrate.

These muscles then act like a valve

by opening and closing the glottis

which is the space between vocal cords.

And that allows air to flow past the cat's voice box.

Now one reason we're pretty sure

this is how purring works

is that cats with laryngeal paralysis can't purr.

So what makes purring so distinctive,

is that it works when cats are both inhaling and exhaling.

And this is why it seems

that they can just keep purring forever.

And while we have a pretty good idea

of how purring works in the throat,

scientists don't 100% agree

on how cats initiate purring.

Some believe that it's a voluntary act initiated

by their nervous system.

So this would mean that cats only purr when they want to.

Sounds very much like cats.

But other studies suggest that the purr signal comes

from a neural oscillator in the cat's brain.

And then still another theory is that purring is caused

by the release of endorphins

when cats experience 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 them or feeding them.

And nursing kittens purr

to let their mothers know they're well

because they can't meow and drink milk at the same time.

So purring is a way to bond with their mothers

and say hey cat mom, I'm A-okay.

But purring communicates more than just happiness.

Upset, injured, sick or even dying cats are known to purr.

And female cats sometimes purr

when they're delivering kittens.

Animal behaviorists think that these cats are purring

under difficult circumstances

because they're comforting themselves.

Now it's also possible that frightened cats purr

to communicate peaceful intentions,

to signal that they are not going to attack.

And so older cats do this sometimes

when they approach younger cats

to say hey, younger cat, I am totally friendly.

Please don't scratch my face off.

Now there's another pretty awesome hypothesis

about why cats purr.

The rapid opening and closing of their vocal chords creates

a sound between 25 and 150 hertz.

And these sound frequencies can both improve bone density

and act as a natural healing mechanism.

There is evidence, in fact, that shows

that purring can repair bones, relieve pain and heal wounds.

And this goes all the way back to an old veterinary legend

that if you place a disembodied cat in a room

with all of its body parts,

they can reassemble their bones together.

Yeah, like Frankencats.

So wait, if other cats can only roar and not purr,

does that also mean

that they don't have these crazy healing powers?

What do you think?

Let us know in the comments below,

and don't forget to loving.