Cats purr for a variety of reasons, not just as a sign of happiness.
Some scientists have found that cats have a unique mechanism in their larynx which causes vibrations to occur when they purr.
A cat’s purring is usually a sign of contentment and happiness.
Many other times, a cat will purr when she is in labor with kittens when she is scared, or with an extremely ill cat.
Cats also use their purr to communicate with other cats.
For example, a mother cat starts using this purr when her kittens are about one week old.
This helps to keep the kittens in close proximity and may also help to identify them by giving a unique “voice” to each kitten’s purr.
Not only do cats use their purrs with other cats, but cats also tend to mimic the pitch of another cat’s purr when they’re in close proximity.
This may be a way for cats to communicate with each other as certain types of purrs elicit different behaviors from the receiver.
How Do Cats Purr?
Scientists have studied why cats purr and they believe that the purring mechanism in a cat’s larynx creates sound vibrations with frequencies between 25-100 Hertz (Hz).
This frequency range lies within the level of human hearing which is roughly between 20 Hz and 20,000 Hz.
To put this into perspective, the best human singers are able to produce sound frequencies roughly between 80 Hz and 250 Hz.
Different species of cats have different purring mechanisms which determine the range of pitches they can make for their purr.
Lions, leopards, and cheetahs (large feline predators) have a mechanism similar to what house cats have, which allows them to make low purring sounds.
The mechanism in the larynx of cougars (large wildcats) is slightly different and gives them the ability to make more higher-pitched purrs.
The reason why a cat’s purr is so unique lies deep within its larynx.
Scientists have discovered special rhythmic muscle contractions which cause vibrations when a cat purrs.
These special contractions are controlled by an oscillator, the same thing that controls the cat’s purr mechanism through neural circuits in cats’ brains.
Hosting 14 muscles, this small area is responsible for making a wide range of sounds including meows, hisses, and growls, as well as purring.
If you interrupted the neural pathway at the point where it led into the larynx, you would not hear a cat purr.
This shows that when a cat’s muscles contract and relax in such a way as to push air over its vocal folds, it will make a purring noise.
The frequency of these muscle contractions determines whether or not we hear a low-frequency purr or a high-frequency whine.
Why Do Some Cats Not Purr?
Cats who have lost their vocal folds cannot make any noise, including a purr.
In these cases, the cat would need to be able to activate its laryngeal muscles by sending electrical signals from its brain to vibrate.
However, this part of the pathway is absent in these cats.
If you have ever wondered why your cat purrs, hopefully, this article has given you insight into this mystery.
We know that it isn’t just a sign of contentment but also functions as a special type of communication between cats.
Maybe next time your cat purrs at your feet while you’re busy at work, you’ll think about this and appreciate it a little more.
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