A cat purrs when it makes a continuous, low-frequency rattling, humming, rumbling, or buzzing noise in its throat.
Cats purr frequently, so anyone who has lived with a moggie will recognize the throaty vibrating sound. Cat owners often compare the sound of their cat purring to the gentle revving of a motorbike engine.
Purring is not unique to domestic cats (Felis catus). Many other wild cat species of the family Felidae also purr, including cheetahs, lynx, ocelots, bobcats, puma, and wild cats (Felis silvestris and F. Lybica).
How do moggies purr?
Experts believe that cats purr through vibrations generated in the larynx (voice box) during the inhalation and exhalation phases of the respiratory cycle.
The air passing over the vocal cords causes them to vibrate under the control of the laryngeal muscles.
An older hypothesis speculated that purring occurs when blood surges through the inferior vena cava in the thorax.
However, evidence supporting the voice box theory comes from the fact that cats with paralysis of the laryngeal muscles can’t purr.
Why does my cat purr?
Moggies start to purr when they are only a few days old. The vocalization by kittens may play a role in mother and kitten bonding.
Cat owners often associate purring with positive emotional or mental states, such as pleasure, happiness, or contentment.
Thus, moggies produce the sound when interacting with their favorite humans or fellow cats.
However, cats may also purr when experiencing discomfort associated with
- Pain
- Injury
- Stress
- Fatigue
- Illness
They also purr
- When they need attention
- During bunting (marking objects with scent glands)
- Before passing out or dying
- When on heat (female)
Purring may heal bone
A cat’s purr is a low-frequency sound between 25-150 Hertz. Studies suggest that sound frequencies in this low-frequency range improve bone healing and density.
Physical inactivity is associated with loss of muscle and bone density. For instance, astronauts experience bone and muscle loss during prolonged exposure to zero gravity in space.
Exposure to gravity on the Earth’s surface offers resistance that helps to maintain muscle tone and bone density.
Cats spend long periods resting and sleeping, making them prone to loss of muscle and bone tissues.
Some researchers believe purring may stimulate cat muscles and bones to reduce loss of bone density and muscle atrophy.
Big cats
Big cats (genus Panthera) generate sounds similar to but different from purring.
Several non-felid species purr. The best-known are members of the family Viverridae, including multiple civet and genet species found in Africa, Europe, and Asia.
Other species that produce purr-like vocalization include the mongoose, guinea pigs, and some Australasian marsupials, such as kangaroos and wallabies.