PurR

Purr is a vocalization most commonly associated with domestic cats. It is a low, continuous, vibrating sound produced by the rhythmic contraction of the muscles of the larynx, which causes the vocal cords to vibrate as air flows through the glottis. The sound can be heard in a range of situations and is often described as soothing or pleasant.

The mechanism behind purring involves a neural oscillator in the brain that drives the laryngeal muscles at a rapid rate, resulting in vibrations that typically fall within roughly 25 to 150 hertz, though individual cats may vary. Purring is usually sustained during both inhalation and exhalation, producing the characteristic rolling hum of the sound.

Kittens begin to purr at a very young age, often while nursing, and many cats continue to purr throughout adulthood. Purring is commonly associated with contentment and social bonding, such as when a cat is relaxed with a caregiver. However, cats also purr in other circumstances, including times of stress, pain, or fear, suggesting that purring can function as a form of self-soothing or a means of communication with humans or other animals.

Functions and evidence regarding purring are not fully settled. The most widely cited theories propose roles in signaling well-being to a caretaker, reinforcing social bonds, and reducing stress. Some hypotheses suggest that the vibrations may promote tissue healing or bone regeneration, but empirical evidence for therapeutic benefits remains inconclusive.

Similar sounds occur in some other felids, though the acoustic and physiological details can differ. Overall, purring remains a distinctive and versatile vocalization most closely associated with domestic cats.