Jorge S. Muñoz
Homeopath and Surgeon Veterinarian.
More than a mere element of communication, the purring allows the
cat not only to tranquilize and to please to its human and feline
family but itself. Also it makes to fortify his familiar relations;
to calm and to make sleep its young or call them to eat; to show
its emotional state; to give samples of friendship and approval;
in order to flatter. It is something more than a feline vocalization
or a physiological peculiarity... stands out by on all the attributes
of the cat. It is personal, singular, distinguishing... is, a true
and matchless piece of art as soon as really talks about to element
of communication and form of feline expression. Whatsoever, the
purring continues being a mystery and until literature no scientist
has taken care of him. A cat personified in the book "The Silent
Miaow" of the author Paul Gallico says: "Nobody until
now has discovered how we make this sound so special... and what
it is more, nobody will do it. It is a secret that has stayed from
the beginning of the life of the cats and will never be revealed."
Nobody is totally safe of how the cat purrs and the reason is that
when an investigator begins to study the mechanism, the kitten stops
to do it. Despite it, we will present the three main theories making
the reservation that none of them is accepted universally.
The first theory says that the cat besides to have its vocal cords
that allow him to emit shouts, miaows, etc., has another group of
structures denominated vestibular folds or false vocal cords. When
the air is inspired and soon exhaled, the friction between both
folds produces the vibration or purring. This theory is losing use
at the moment.
The second theory talks about the contraction of some laryngeal
muscles that produce a modification of the pressures with the consequent
appearance of vibrations.
The third and most convincing at the moment is the related to the
turbulences produced by the sanguineous flow. One says that the
purring is a phenomenon of hemodynamic origin before that aerodynamic.
The concrete vibration is originated in a great vein, posterior
vena cava* in the thoracic cavity. Where it crosses the diaphragm,
the contraction of muscles around compresses the sanguineous flow
causing a transition of smooth flow to turbulent flow producing
oscillations similar to the flutter movement of a flag. These vibrations
soon are transmitted and amplified by the full of air bronchi and
the trachea towards the sinus of the head.
The greater support of this theory comes from the case of a Manx
cat that was attacked by a dog. In spite of having rupture of diaphragm
and trachea and not being able to emit sounds because of its injuries
and medical procedures applied to save its life, the cat still purred.
Emission of sounds through its throat was not observed, plus the
vibrations were easily detectable in its thoracic cavity. In other
animal victims, also it could settle that the rate of the purring
was not synchronous with the heart rate or respiratory rate, indicating
therefore an independent mechanism. The theory of the turbulence
also maintains that when the cat bends its back, that elevates the
speed of the blood and therefore the purring is more intense. When
you caress your kitten and it bends its back, you will notice that
the purring will increase its volume and intensity. The same happens
with a furious cat or when it is in danger that it emits a vibration
of high tone that easily is perceived but rarely heard.
Anyone is their physical mechanism the feline purring symbolizes
the capacity of self expression and its desire to communicate, although
We were spoken, why not they? Many investigators consider that it
represents an emotional unloading, a true measurement of depth.
A cat crossing for a moment of great emotion (satisfaction, joy,
fury, pain) purrs. It has happened to many of us in the professional
exercise to listen to a deep purring resonating in a very hurt or
dying animal... perhaps that rhythmical vibration produces the comfort
sensation to them that is needed in that delicate situation.
Some investigators have demonstrated that when it pass a hand over
a cat purring, it can make simultaneously to go down to the pressure
and the sanguineous pulse that to increase the sensations of peace
and well-being. Anyone who lives with a cat can testify of the tranquilizing
and still hypnotic effects that a cat has purring in his knees.
Randy Moravec, in his book “Claude” directly attributes
to the purring the reason of the domestication of the cat by the
human and says: "the cat does not make much, is of little eating
and pleases to leave to hunt single. On the other hand, being so
soft, having a beautiful skin and giving a pleasant purring, it
had been accepted by its aesthetic value". In this book it
emphasizes that a cat during all its life spends more than 10950
Did you count the hours of his cat...? Accept the challenge to participate
in the Guinness book.
Has some meaning the purring? And if thus is… which? Those
questions are formulated by people that study the communications
between the animals and the creatures whereupon they interrelate.
They investigate his form, content and context looking for tracks
of motivation and attempt.
Some people define two types of purring: the Post appreciative
or Thanked and the Anticipatory. Both are useful to manipulate the
human vanity. The first will be dedicated to who did or gave something
to it of his affability. The second is a powerful stimulant to obtain
what it wishes.
Another important purring is the one of Halting, very effective
to let you know that a transgression towards it has been committed.
Between those of its species, the purring has a great variety of
communicative functions. A cat accompanies its work by childbirth
with continuous, powerful and rhythmical purring. As each young
is born, weak, blind, without much sense of the ear or sense of
smell, the vibrations of the mother act like a signal to help them
to find their place to suck.
Surely the purring also helps the mother to calm allowing to concentrate
itself and to eliminate of its mind everything what it bothers it
or it distracts at those so important moments.
When the kittens are 2 days of age, spontaneously they begin to
purrs while they suck. Those vibrations help them to orient themselves
and they serve the mother to know that the milky flow is the correct
and that it is all good... would be like the smile of a baby.
As the kittens grow they are called to eat with a fort and powerful
All these "communitarian" purring serve to create and
to maintain a narrow familiar relation in the first weeks of life
in which the necessity of protection from the part of the mother
In the adult cats the purring sometimes is used like a signal of
submission of a cat opposed to another dominant. In these cases
the possibility of a fight of an attack is reduced distracting to
the aggressor or stimulating in its mind feelings of peace and conciliation.
A female purrs almost continuously during the courtship and the
Each cat has a peculiar form to purr and the intensity varies widely
from one to other according to the situation that induces them.
Some cats purr with enthusiasm, others however only whisper quiet
and with honor; there are those that make ostentation of his rough
purr although not less wizards, others have purr as whispers and
whistles; finally they are those so discreet that its purring only
can be detected caressing its throat... feeling, more than listening
to his velvety vibrations.
The mystery and sensuality of the feline purring have captivated
to not few poets and writers and it is materialized for example
in some musical metaphors. Thus we see it compared to the sound
of "the kettledrums in the Berlioz Requiem” or several
references to the repertoire of Tom Jones: "it sounds equal
a low tone", "they are like low drums touched very smoothly".
The frequency of the purring, like a bed of corporal massages,
is considered that is of 60 c/s and from which both have a similar
effect on people. For that reason it is that many people speak of
the "therapy of the purring" adding that is economic than
tranquilizers and free of collateral effects. The purring is, beyond
all doubt, a force of the good in the world.
An author and expert in animals, Roger A. Caras, poeticize about
the beneficial effects that it would have on the human if this one
acquired the ability to purrs: "the people who purrs would
feel happy with the people around him and with himself. Imagine
the situation in an elevator when you are pushing by other people
and for that reason you strike them and these purr instead of dedicating
insults to you... Then, you also instead of saying mechanically:
"I am sorry" would answer with a purring... ".
Finally, we will say that the great felines as the lion or the panther
can purr although with limitations and without the amplitude of
the small felines. Like compensation, they can roar... thing that
our kittens or intermediate felines like the puma don’t make...
*) Posterior vena cava has it origin from the union of the iliac
veins of the posterior members to the height of the 4th. –
5th. lumbar vertebrae. In its route it receives the sanguineous
contribution of the abdominal and genital vessel. After crossing
the diaphragm it ends at the right auricle.
Data collected from Forovet - 2003
Health and Joy.
Until the next one.