Do cats just purr when they're happy?

Everyone knows that a purring cat is a happy cat. Don't
they? But could there be other reasons for a cat to purr?

Felines are, interestingly, one of only a few species that
purrs (others include rabbits, raccoons, lemurs, and even
elephants!) but not all types of cats purr.

Cheetahs and servals can purr, but other big cats (like
lions, leopards, and jaguars) only purr when breathing out
– they can't purr continuously.

Cats certainly purr when they're happy and relaxed. But a
mother cat will purr when giving birth, and they also purr
when they're frightened, injured or in pain - or dying.

So there must be reasons for purring other than to show
contentment.



Kittens learn to purr from their mothers

Newborn kittens are blind and deaf, and it's believed that
mothers purr to let their kittens know where they are and to
tell them to feed.

Although the kittens can't hear when they're first born, they
can feel their mother's vibrations, which draw the kittens to
her.

Kittens learn to purr themselves at around one week old,
and it's thought that their purring is a signal back to the
mother, letting her know that they're feeding and that all is
well.



Purring as a sign of friendship

There is a theory that purring could be a sign of friendship,
a way for a cat to show that it's in the mood to socialize, or
perhaps to communicate that it isn't a threat.



Why do cats purr when they're ill? Good vibrations

Researchers now believe that the vibrations of purring may
have a purpose in stimulating self-healing.

Veterinarians have long known that a cat heals more
quickly than a dog, and in humans, vibrations have been
shown to help relieve pain, and also to stimulate
circulation and the growth of new tissue.

One study measured the sound frequencies of cats' purrs
and discovered that this happens between 20-200 Hz (and
in particular, 25 Hz, 50 Hz, 100 Hz, 125 Hz, and 150 Hz).

The fascinating thing is that these frequencies correspond
precisely to those that been shown to help bone growth,
pain relief, and the reduction of inflammation in humans.

It's also felt that purring may stimulate the release of
endorphins – the morphine-like feel-good chemicals made
in the brain. Endorphins are natural pain-relievers so
perhaps the main point of purring is to help a cat to recover
from injury - to reduce pain and heal itself.



Could it be a form of exercise?

An article in Scientific American written in 2003 speculates
that because cats have evolved to save energy (they spend
around 17 hours a day resting or sleeping) it may be that
purring has evolved to stimulate muscles and bones
without movement – a form of passive exercise, perhaps?



Purring can be a request for food

A recent study by scientists at the University of Sussex
demonstrated that purring may be a way for a cat to let its
owner know that it's are hungry.

According to Dr. Karen McComb, who led the team, purring
as a request for food is hard to ignore. This type of purring
sounds insistent – urgent, even - and has a meowing,
crying sound mixed in with it that owners say is very
different to their cats' normal 'happy purr'.



Why do cats stop purring?

Sometimes, a cat will stop purring as it ages. We don't
really know why this happens, but it may just be that it
purrs so quietly that you don't hear it. Feel for the
vibrations, instead.

If your cat stops purring and seems to be in any pain, have
him checked out by a veterinarian, just in case there is
anything seriously wrong.



Why do cats purr? What does your cat's purr mean to you?

It's possible, of course, that we'll never truly find out the
answer to 'why do cats purr?' - but it's always fun to
speculate.
Whatever the official verdict, most cat-owners can interpret
their own cats' purring. It's purrrrfectly clear!



My cat purrs to say:

Where have you been?
I want to go out
I'm hungry
Mmmm, this snack's good
I want a cuddle
I'm happy
Please rub my tummy
Please rub my tummy some more

And of course ...

I love you!