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The purring of the cats
 

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 with itself...
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 hours purring...
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 purring.
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 is absolute.

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 sexual act.

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.

 

 

 
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