Your cat is curled up on the pillow, eyes closed, and suddenly you hear a low and rhythmic sound: he is purring while being sound asleep. It is a sweet experience, but also a fascinating mystery.
The Purr: What Is It Really?
The purr is a low-frequency vibration (25-150 Hz) produced by the muscles of the larynx, which modulate the incoming and outgoing air. It occurs almost continuously, without interruption between inhalation and exhalation.
Why Does a Cat Purr in Its Sleep?
1. Deep Relaxation
A cat's sleep goes through alternating phases: light sleep, REM, deep sleep. In the most relaxed moments, especially during light sleep phases, purring expresses pure bliss.
2. Self-Soothing
Researchers have discovered that purring has a self-soothing effect. When a cat purrs in its sleep, it is literally "rocking" itself.
3. Response to Pleasant Stimuli
If you pet the cat while it sleeps, it may start to purr even without waking up. This means it recognizes your presence as positive, even unconsciously.
4. Pleasant Dreams
During the REM phase, cats dream. They may move their paws, sigh, and sometimes purr. They are likely dreaming of something nice (successful hunting? A loved cuddle?).
The Purr and Health
Purring is not always synonymous with happiness. Even sick, painful, or stressed cats can purr to self-soothe. Frequencies between 25-50 Hz even have healing effects (they seem to accelerate bone healing).
When to Worry
- Purring accompanied by labored breathing or whimpering.
- Sudden changes (a previously quiet cat that starts purring a lot, or vice versa).
- Excessive lethargy, loss of appetite.
In these cases, a vet visit is advisable.
Curiosities
- Tigers, lions, and leopards do not purr: only smaller felids do.
- A cat's purr can reduce the owner's stress and blood pressure: free therapy!
In Conclusion
A cat purring in its sleep is almost always a serene cat, at peace with the world. It is the sound of feline love: listen to it, embrace it, and consider yourself lucky to have such an affectionate creature by your side.
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