Some cats purr when they are happy, while others seem to do it when they are ready to pounce. This leads often-exasperated owners to wonder ‘Why is my cat purring so loudly?’
Cats purr loudly to express contentedness, to calm their nerves before aggression, and even purr to help with their breathing, manage pain, and promote healing! While purring is pretty basic as a kitten, it gets nuanced as it gets older and we’re going to explain it in a little more detail for you today.
While we don’t fully understand everything about it, there have been numerous studies that have unlocked some interesting facts about your kitty’s ‘purr-box’ and we’re going to share them today. Read on for a comprehensive look at purring – including thins like decibels, vibrations, and ‘when purrs go bad’!
What is purring, anyway?
Purring is has to do with vibrations produced by the laryngeal muscles that produce a sound that runs seemingly on ‘automatic as your cat’s respiratory system does what it’s designed to. The tone produced is unique to each cat, with some purrs being quite low, while others rumble at a ‘mini-seizure’ grade of vibration!
The reasons that a purr might come up are many and varied as well. Some cats will purr when you give them new, yummy food, or whenever they sit close to you.
Other cats might start purring when they are about to attack your feet – though these purrs will usually be accompanied by a swift ‘back and forth motion from the tail. Most often purring is a sign of happiness and contentment, however, and if you pay close attention then you’ll notice when the intensity changes.
Make a mental note when it does – as this is the ‘fast-track’ to learning the things that your kitty likes the most.
Average Cat-purr in decibels
Most cats are going to purr at around 25 decibels. In order to paint you a mental picture of this, let’s take a look at some comparable decibel levels from common sounds. Here are a few examples for you:
- A refrigerator is twice as loud as your cat’s purr, at a whopping 50 decibels.
- Your breathing is less than half of the volume of your kitty’s purr, at a mere 10 decibels.
- Whispering from a distance of about 5 feet away is pretty close, registering at 20 decibels, while someone whispering just 2 to 3 feet away from you is about 30 decibels.
- Even a library is louder than your cat – averaging at 40 decibels, provided that the Librarian is enforcing the silence!
So, as you can see, it’s hardly loud enough to cause a fuss, although some cats do sound like cute, little motors, while with others you can hardly tell that they are purring at all. Let’s take a look now at the vibration range of purrs for a more comprehensive understanding of your cat’s ‘appreciation/aggression engine’.
The vibration range of purrs
The standard vibration range of the purr of most cats is 20 to 140 Hz. Now, you might be wondering ‘what is that good for?’ and we’re glad that you’ve asked about that. As it turns out, this vibration range is quite soothing – much like a massage chair is for us – but your cat gets to have a built-in model.
It’s enough to make a little jealous, but we digress.
As far as what those rages are good for, we actually have a pretty good idea. Let’s take a look at the therapeutic aspects of these vibrations so that you can see it for yourself. The data below comes from a study done by the Acoustical Society of America:
- Domestic cats, as well as their wilder cousins, such as Ocelots, Pumas, and Servals often produce a purr ranging from 25 to 50hz, which just so happens to be ideal for bone healing and growth!
- All of these cats share a common frequency that they will use from time to time – 100 Hz – and this frequency of vibration is good for suppressing pain and increasing recovery time from wounds.
- Cats can also purr at certain ranges that help with breathing issues, such as Dyspnea.
It’s really quite fascinating, but apparently their purring does indeed serve a purpose besides letting you know that they like having their ears scratched. It can help them breathe, recover from damage, and even strengthen bones and joints. Nature definitely knows what she is doing when it comes to the cat’s purr.
Cat purring changes over time
Another interesting thing about cat purrs is that they change over time. While the expected changes, such as purring becoming louder and stronger are to be expected, the actual meaning of the purrs will change as well.
When your cat is a kitten after they’ve been alive for 2 to 3 days, their ‘purr-box’ starts working and mom will use it to find them when it’s time to feed her kittens. They will also purr when they are nervous, such as when exploring a new place or when a human suddenly scoops them up for a quick cuddle.
Mothers also use a deep purr to announce to the kittens that she is available. As cats get older, they will purr for each other during grooming, possibly as a way to say ‘I like this, more please!”, and some cats will purr to ‘steady their nerves before a pounce – so be sure to watch your kitty’s body language.
The thing is, while we know a little about purrs, experts like Veterinarian Gary Weitzman of the San Diego Humane Society tell us that we’re just beginning to understand it.
We’ve isolated the trigger, which is a neural oscillator called the infundibulum and it only seems to be related to purring, but beyond this there is still a lot of mystery about cat purrs that we have yet to understand.
Why do some cats purr louder?
It’s all about the strength of the vocal cords. As a cat gets older, for instance, their purr will definitely get louder, but that’s simply because their vocal cords are getting lots of use and strengthening over time.
Some cats are born with strong vocal cords and you’ll know which cats these are right away, as they’ll be the loudest kittens in the litter.
That doesn’t mean, of course, that your kitten is going to be a chatterbox – it’s up to the individual cat – but it DOES mean that they will have a much more robust purr than the average kitty. Speaking of robust, let’s take a look at the cat that Guinness has recorded as having ‘the loudest purr on record’.
The loudest cat purr on record
While you may have heard rumors that this cat purrs at 100 decibels, that’s only because this is what the owner initially believed.
‘Merlin’ the cat, a rescue kitty from Devon, England is a 13-year old cat that purrs at a measured 67.8 decibels. While cats have a higher range, with Merlin this volume is consistent, and it’s earned him a spot in the record books. If you’d to hear just how loud little Merlin can get, you can check out a video here.
Is purring ever bad?
All purrs are not created equal, as it turns out, and you need to pay close attention to your cat’s body language to make sure that you don’t reach out to pet your kitty, thinking that they are happy, and end up with a nasty scratch for your troubles!
As kittens, purrs are all about being fed, getting fed, and as a response to grooming or fear. As cats get older, they’ll also use their purr to calm themselves in preparation for a strike! The calming influence of the purr washes anxiety away so that your cat can focus themselves for a brilliant and perfect pounce.
Signs of this can be intent staring, with an overall tension of the body, and if your cat is getting close to that moment of aggression, then you will usually see a swishing of the tail. Some cats even take it a step further, and they’ll make a ‘rusty metal’ type of growl or meow as their final warning.
If you notice any of these behaviors, then that purr is not a good thing – it’s time to back off and give your kitty a little space. Trust us – it’s best for both of you!
Some Cats purr without touch
Purring can be done on purpose or as an involuntary response, often to something that’s not readily apparent without taking in the context. For instance, some cats will just sit down somewhere and start to purr without you even touching them.
While we believe that this is likely subconscious or conscious ‘anticipation’ of being petted, we simply don’t have enough data to be 100% sure.
As we mentioned previously, purrs are believed to help with healing and calming your kitty, and as no two kitties are completely in agreement as to what deserves a purr, it’s an awfully difficult thing to study.
So, your cat could be purring in anticipation of petting, they could be calming anxiety, or even healing an ailment that you aren’t aware of. For now, those purrs just support the cat’s reputation for being ‘mysterious’ and more study is going to be needed to ‘crack the code’.
A purr-fect ending
Today we’ve shared what is known about purring and as you can see, it’s a complicated thing. Cats purr when happy, nervous, and even when they are mad – so you need to pay attention to context. Ultimately it’s about getting to know your cat and in time you’ll know EXACTLY why they are purring so loudly – it’ll all be there in their body language!