Why do cat's purr, and what purpose does it serve?

Answer 1

cat's purr just like baby's make their sounds of comfort when suckling. Their vocal cords are pretty loose to let them make their shrill cries when needs, so it vibrates.

a cat's shrill cry is like a mini rour of a lion... both sounds if one anylises the voice box whilst made, are seen to have the same configiration, of course there is no need to look to make such a complicated operation, as we can simply see on a sound graph.

Answer 2

Most experience "cat wranglers" now know that cats don't purr only when they are content and happy. They also purr during tense or traumatic moments. When suddenly and violently injured, even at moments near death, a cat will often purr.
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Look at the website, it'll tell you more.

Answer 3

there can be many reasons why they purr the purpose is to let u know they are happy or upset or whatever there feeling

Answer 4

It's the same as dogs wagging their tails their just showing their emotions