NON-Heart how purrs are secret to cats' nine lives
- Hi Everyone,
I posted this on the crf list a while back and since the
topic of purring has come up here I thought you might
like to read it as well.
Revealed: how purrs are secret to cats' nine lives
By David Harrison, Environment Correspondent
SCIENTISTS have discovered that the purring of cats is a
"natural healing mechanism" that has helped inspire the myth
that they have nine lives.
Nine lives: wounded cats purr because it helps their bones and
organs to heal Wounded cats - wild and domestic - purr because
it helps their bones and organs to heal and grow stronger, say
researchers who have analyzed the purring of different feline
species. This, they say, explains why cats survive falls from
high buildings and why they are said to have "nine lives".
Exposure to similar sound frequencies is known to improve
bone density in humans.
The scientists, from the Fauna Communications Research I
institute in North Carolina, found that between 27 and 44
hertz (a measure of the number of cycles per second) was
the dominant frequency for a house cat, and 20-50Hz for
the puma, ocelot, serval, cheetah and caracal. This reinforces
studies confirming that exposure to frequencies of 20-50Hz
strengthens human bones and helps them to grow.
Dr Elizabeth von Muggenthaler, the president of the institute,
said: "Old wives' tales usually have a grain of truth behind them
and cats do heal very quickly. The healing power of purring
seems to explain their 'nine lives'."
The scientists say that sound waves created at a particular
frequency trigger the healing process in feline bones. Purring is
believed to have a similar effect to ultrasound treatment on
humans. Dr von Muggenthaler said: "We are starting to solve
a 3,000-year-old mystery as to why cats purr. the next phase
will be to explain the mechanics of the process."
Almost all cats purr, including lions and cheetahs, though not
tigers. Dr von Muggenthaler said that purring had to be
advantageous to a cat to survive natural selection, but there
seemed to be no obvious advantage for a cat merely to display
contentment. A natural capacity for increasing bone growth and
strength and reducing healing time was, however, "clearly
Cats' ability to survive and recover quickly after falling from tall
buildings is well documented. One recent study, published in The
Journal of the American Veterinary Medical Association, found that
out of 132 cats that fell an average of 5.5 stories, 90 per cent
survived, including one that fell 45 stories.
Other scientific teams are researching whether "sound treatment"
could be used to halt osteoporosis and even renew bone growth in
post menopausal women. Dr David Purdie, from Hull University's centre
for metabolic bone disease, said that the human skeleton needs
stimulation or it begins to leak calcium and weaken. "Purring could be
the cat's way of providing that stimulation for its own bones."
He said that it was difficult to devise physical exercises for old
people suffering from osteoporosis and speculated that it might
be possible to create a mechanism to use cats' purring to help
strengthen elderly bones.
Cynthia, Taffy, Samuel