Why do cats purr?
Purring isn’t just contentment; cats use it to communicate, even hiding a “feed me” cry inside it. A 2023 study found the cat voice box can purr without any muscle input.
Quick Answer
Cats often purr when they’re relaxed, but purring is also communication. A 2009 University of Sussex study found cats can hide a higher-pitched, cry-like sound inside their purr when they want to be fed, and even people who had never owned cats rated those purrs as more urgent. How cats purr has long been debated. A 2023 study in Current Biology found that a cat’s voice box can produce purr-range sounds, about 20 to 30 vibrations per second, with no nerve signals or muscle contractions, thanks to special pads in the vocal folds. It’s similar to the “vocal fry” in human speech. Not every cat purrs: cheetahs and cougars do, but lions, tigers, leopards and jaguars roar instead.
By the Numbers
Key Facts
- Purr frequency
- About 20–30 vibrations per second at its base
- How it’s made
- Pads in the vocal folds let the voice box vibrate that slowly (2023 study)
- Hidden message
- A cry-like sound embedded in purrs when cats want food (2009 study)
- Big cats
- Cheetahs and cougars purr; lions, tigers, leopards and jaguars roar
Who purrs, who roars
| Purring cats | Roaring cats | |
|---|---|---|
| Examples | House cats, cheetahs, cougars | Lions, tigers, leopards, jaguars |
| Hyoid bone in the throat | Fully bony | Partly bony, with a flexible larynx |
| Purrs continuously? | Yes, breathing in and out | No |
More than a happy sound
Purring often signals a relaxed cat, but it’s also a tool for communication. In 2009, researchers at the University of Sussex found cats can add a higher, cry-like component to their purr when asking for food, and people judged those purrs as more urgent and less pleasant.
How the purr is made
For decades, scientists assumed purring required rapid, rhythmic twitches of the voice-box muscles. In 2023, a team led by voice scientist Christian Herbst showed that cat voice boxes, studied outside the body, could still produce purr-range sounds from airflow alone, thanks to fleshy pads within the vocal folds.
Why lions roar instead
Roaring big cats have a partly bony hyoid and a flexible larynx built for powerful, low roars, an anatomy that rules out continuous purring. Cheetahs and cougars, with a fully bony hyoid, can purr but can’t roar.
Myth vs. Fact
MythScientists fully understand how cats purr.
FactIt’s still debated. A 2023 study showed the voice box can purr on its own, challenging the long-held idea that muscle twitches are required.
MythAll cats purr.
FactLions, tigers, leopards and jaguars can’t purr continuously the way house cats, cheetahs and cougars do.
The Bottom Line
Cats purr to communicate, not only to show contentment, and they can even tuck a cry-like “feed me” into the sound. Special pads in their vocal folds let them rumble at about 20 to 30 vibrations a second.
