# Why does a cat purr when you pet it?

**URL:** https://boards.straightdope.com/t/why-does-a-cat-purr-when-you-pet-it/673580
**Category:** Factual Questions
**Created:** [November 10, 2013, 4:24pm UTC](https://boards.straightdope.com/t/why-does-a-cat-purr-when-you-pet-it/673580 "2013-11-10T16:24:26Z")
**Posts on this page:** 3
**Page:** 2

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### Author: ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)
#### Post date: [November 14, 2013, 8:19pm UTC](https://boards.straightdope.com/t/why-does-a-cat-purr-when-you-pet-it/673580/21 "2013-11-14T20:19:53Z")

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Little kittens purr almost constantly during the first month or two after birth.  
Somebody\* once suggested to me that it was an evolutionary thing…the mother cat can hear each of her babies and know that they are okay and happy.

I’ve never heard anybody else suggest this, but I like the idea. Because there ain’t nothing in the world that’s cuter than a purring kitten.

\*a teenage clerk at a pet shop.

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### Author: ![brettster55](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brettster55](https://boards.straightdope.com/u/brettster55)
#### Post date: [November 14, 2013, 9:38pm UTC](https://boards.straightdope.com/t/why-does-a-cat-purr-when-you-pet-it/673580/22 "2013-11-14T21:38:08Z")

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Cats also pur when they are in pain

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### Author: ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)
#### Post date: [November 14, 2013, 11:31pm UTC](https://boards.straightdope.com/t/why-does-a-cat-purr-when-you-pet-it/673580/23 "2013-11-14T23:31:40Z")

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> [@TimeWinder](#):
>
> Um, it’s a biological function. We don’t know how our brain works (and for millennia we didn’t know how ANY of the body works), but we still manage to learn to use our capabilities. I can’t explain to you the mechanism of a sneeze, but I still manage to do it just fine.

My post was really meant to be a bit whimsical. A sneeze isn’t a learnt action, indeed I challenge you to sneeze at will. Language is learnt, although we need some innate capability to build it on.

As a counterpoint, yodelling might be a human equivalent - and that is most certainly not innate. But, if the theory on specific wiring in cats to modulate vocal cords is correct, the answer is that purring is not learnt, although the social use of purring probably is.

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