A small motor, several meanings
Cats purr in several situations, including relaxed social contact, feeding as kittens and stress. Purring does not always mean a cat is happy.
A cat curled beside you may sound as though someone has left a tiny motor running. It is a familiar part of life with cats, but the noise is not a complete translation of how they feel.
The kitten connection
Cats Protection describes purring as part of the bond between kittens and their mother. It can help kittens signal where they are and that it may be feeding time.
In adult cats, it can accompany contentment or a request for attention. Cats can also purr when stressed or in pain. The situation and the rest of their behaviour matter alongside the sound.
There is a throat mystery too
In a 2023 laboratory study reported by the University of Vienna, cat voice boxes produced sounds at purring frequencies without repeated nerve signals driving muscle contractions.
Soft pads in the vocal folds may help explain those surprisingly low sounds. The researchers also said our understanding remains incomplete. Producing a purr-like sound in the laboratory does not explain every purr from a living cat.
A familiar animal, more to notice
The same cosy rumble can appear in different situations. It is an intriguing sound, rather than a built-in happiness meter.
For another feline puzzle, discover why cats are so fond of boxes. Or meet another misunderstood animal: bats can see as well as use echoes.