CURLING UP WITH your favorite ball of fur as she purrs away is pretty close to heaven, at least for cat folk. Yet, hidden between those vibrations, that most appealing of domestic sounds remains wrapped in mystery, and even a little magic.
No one is certain exactly why cats purr, though there are a number of good guesses. The obvious observation is cats seem to purr when they’re pleased and feeling good. But that’s not always the case: Some cats also purr when they’re hungry, injured, or frightened. And most surprisingly, purring frequencies have been shown to stimulate bone regeneration—yes, bone regeneration.
Cats purr by using their larynx and diaphragm muscles, both as they inhale and as they exhale, although just how the central nervous system generates and controls those contractions isn’t yet understood. Early 19th century taxonomists thought cats could either purr or roar, and split the family Felidae along these lines—“purrers’ (subfamily Felinae) and ‘roarers’ (subfamily Pantherinae).