That gentle rumble from a contented cat is one of the most soothing sounds in the pet world. But what is happening when your cat purrs, and why do they do it? Purring is more than a sign of a happy cat. It's a form of communication, and it may bring benefits to cats and humans alike.

The Mechanics: How Cats Create That Special Sound

Cat purring

A purr begins in the brain. Nerve signals trigger fast vibrations in the muscles of the larynx, or voice box. Cats make the sound while breathing in and while breathing out, which is why a purr is steady and continuous rather than coming in bursts.

The purr also has its own acoustic character. Domestic cats tend to purr at a frequency between 25 and 150 Hz, produced as the vocal folds open and close rapidly. The result is alternating waves of sound across both phases of the breath.

Purrs vary from cat to cat. Older cats often purr more loudly than younger ones, though the underlying pitch can sit a little lower. Each cat has their own purring signature, much like a human voice.

We tend to link purring with happiness, and cats do purr in several situations. The most familiar is during good experiences, such as being stroked by a favourite person, at feeding time, or while settled somewhere comfortable. But purring turns up in some less expected moments too...

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Research rating: ⭐⭐⭐⭐ (4 of 5). Last updated 25 August 2026.

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