Even the smallest of kittens knows how to purr. It is a strange, sound, made deep in their throats to express a feeling of contentment and security. Older cats also purr when they are ill so it is not always a sign of contentment.
The purring mechanism is not fully understood by animal behaviourists: it is a vibration rather than a full vocalisation (although, of course, all sounds are caused by vibrations).
While most sounds in mammals are made by vibrations of the vocal chords, purring seems to have a different source. At one time it was thought that purring was caused by the sound of blood pumping through one of the main veins in the chest cavity. However, it now seems clear that the sound is due to muscular movements.
Research has shown that sick cats often purr: in particular, cats that are incubating cat ‘flu often purr loudly. It could be that your cat is sickening for something, so keep her warm and provide plenty of fluids.
The rubbing is her non-vocal form of welcome. She is marking you to indicate that you’re part of her territory. She keeps her purring for when she is happy and relaxed, rather than when she is interacting with you.
Kittens purr before they can see or hear when they’re a week old.
When a cat purrs, the muscles in the larynx (throat) and diaphragm (between the stomach and the lungs) contract alternately with a rapid, even rhythm. These contractions cause the vibrations deep within the cat’s body that are heard as a smooth, purring sound. Kittens learn this sound at an early age, because when they are born it is usually the first thing that they are aware of.
- When kittens are born they are blind, deaf and have no sense of smell. So the vibration of their mother’s purr is the main stimulus they have, and they soon learn to home in on it.
- Queens often purr while they are giving birth: this can be a painful process, so purring is not just a sign of contentment. They may be reassuring their kittens as they come into the world.