It’s a question every cat owner asks themselves at least once in their life: Why do cats purr? If you’re like most people, you probably assume the answer is fairly simple. We’ve always interpreted cat purrs as a sign of contentment and comfort. But, as with almost everything else cat-related, it turns out the actual answer might be more complicated. A lot more complicated.  

In fact, scientists still don’t know for sure exactly how cats purr. There was a theory that it had something to do with increased blood flow in the inferior vena cava, but new theories suggest that cats might have a unique ability to constrict their larynx around their vocal cords in order to cause vibrations. 

In any case, while the mechanics of how cats purr remain a mystery, at least for now, the reasons why cats purr are even more difficult to parse out. Let’s take a look at some of the most likely possibilities. 

Why Cats Purr: Contentment is Just the Start. 

There’s no denying that cats purr in part because they’re happy. But how do you know if this is why your cat is purring in any given situation? 

Body language: Look at their body language. Is their posture relaxed and natural or are they stretched out on the couch with a “cat smile?” If so, there’s a good chance that your cat is purring because they’re one happy little critter. And that’s always a win. 

Healing: Of all the potential explanations for cat purrs, this one might be the most interesting. There are some studies that suggest purring might be connected to both mental and physical healing. Amazingly, these benefits might extend to their owners as well, meaning there’s a scientific explanation for why petting our cats makes us feel better.  

In fact, purring in cats releases endorphins in both them and us. These endorphins, in turn, contribute to lower blood pressure, a better mood, and reduced anxiety. On top of that, the frequency at which a cat purrs (about 25-140 Hz) has been linked to faster bone and muscle repair. Now that’s impressive. 

Stress Relief: Beyond contentment and amazing healing capabilities, many cat experts believe that cats might purr to self-soothe. Again, this is due to the frequency at which they purr. 
Cats in stressful situations—think car rides, going to the vet, or having strangers in the house—might actually be purring because they’re trying to manage their own stress levels. So the next time your kitty is purring in the vet’s office, it might be a good idea to provide a lot of comfort and reassurance.   

One of the more straightforward explanations for the question of why cats purr is that they’re communicating hunger. This one should be easy to figure out. If it’s dinner time and your kitty starts to purr the minute you grab the bowl, hunger is probably the cause.  

Why is this the case, you may ask? It might start when they’re kittens. Purring might be one of the primary ways that mother cats and kittens communicate with one another. A mother cat might start to purr while giving birth (there’s more support for the stress-relief theory) and continue to purr after labor to help her kittens find her. It’s also been noted that kittens pick up on this quickly, recreating the sound to signal their hunger. 

Why Do Cats Purr? It Depends. 

Why do cats purr? The most likely answer is: it depends on the context. If nothing else, purring is another tool in a cat’s communication repertoire. And, just as cats have figured out how to talk to us through meows, they have probably fine-tuned their purrs for human interaction as well. 

In fact, one study found evidence to support the theory that cats are so in tune with what makes us humans tick that they can insert a “cry” into their purr. Otherwise known as solicitation purring, it’s a highly effective way of getting attention for some reason or other. It even shares some qualities with an infant’s cry.  

All of this adds up to one conclusion: cats purr for a lot of different reasons. If you want to know the specific reason behind why your cat is purring, you’ll probably have to meet them halfway to figure it out. 

Really, who expected anything less?