As a cat owner, I love the hypnotic sound of a cat's purr. But, I've always asked myself the question, "Why do cats purr?" So, I decided to do some research on the topic and found some interesting answers.
Weird Science - My Homegrown Investigation
The initial investigation started right here in my own home with my family of cats. I have eleven cats that I have rescued over the years and they are of varying breeds and personalities. Personally, I felt eleven subjects were enough to make a good home-based experiment, wouldn't you agree? Over time and under different circumstances, I began to note when I observed my cats purring and here are my findings.
Happy
My first cat Liberty came into my life after showing-up on my front door step on Liberty Street, which is how he got his name. He walked up to me and started to rub around my legs and was purring. Anytime I'm in front of my computer blogging, my big orange tabby, Neko jumps into my lap and starts to purr... now that's a happy cat.
Content
My little firecracker kitty named Chiwa is always running around, jumping and playing. When she finally settles down and is just lying around on the couch after a nice meal, she seems to be completely content and purring. I've observed her while she is alone and she just purrs away while relaxing.
Hungry
This observation is a little confusing but, here it goes. When Neko and his litter-mate Domino were born to their mother Chloe, I noticed as kittens while they were still unable to see, they would purr. Chloe would then come near, lie down and she would begin to purr. The kittens would then zero in on mom like a radar and start nursing. So, does the mother hear the purring of her kittens and respond to their hungry cries by purring herself which audibly guides the kittens to the mother to feed?
Sleepy
My black cat, Sammy is an athletic and high energy kitty. He's also a teenager and is constantly playing with the older cats and two kittens, Chiwa and Lydia. He runs himself as hard as he can, literally fighting sleep. But, when he comes in and is completely exhausted, he seems to purr extremely loud, then flops down and purrs himself to sleep.
Hurt/Injured
Our toughest cat has to be Oliver (aka Ollie or Mr. Bubbles as we like to call him). He was named after the street that we found him on; he was barely alive after being hit by a car. He had severe injuries to his head causing paralysis and blindness from brain swelling. Also, he had a broken hip, shoulder and tail. We stabilized his body in a stiff cardboard box to transport him to an emergency animal hospital. The whole time he was purring? I believe he was purring because he was injured and scared and it brought comfort to him.
Fear/Scarred
We have a 4,000 square foot yard that is fenced in with special cat fencing to contain our family of cats. Occasionally, a neighborhood stray or feral cat will come around and approach the fence. When this occurs, approximately 8-10 of our cats will gather in a semi-circle about 4 feet from the fence and stare the poor stray cat down. I've noticed that some of our cats will start a pattern of growling and then purring then growling again. They will continue this pattern until the offending stray leaves the area. I believe our cats are nervous or fearful of the stray cat during this confrontation of growling but then have a need to calm themselves to prepare for a fight or to at least make a stand.
Is This An Elaborate Form of Kitty Kommunication?
After all my observations over the years, I've come to a conclusion that this purring must be an elaborate form of kitty communication. There has to be some scientific or biological reason why these feline frequencies are being emitted by our cats under different circumstances. So, I decided to hit the internet to find a scientific explanation.
Real Science - What the Nerds Say
Well, there seems to be some interesting scientific theories that explain the question, "why do cats purr?" Let's take a look at several theories below.
Purr Frequency
The tonal range of a cat's purr is 25hz-250hz, which is 25 to 250 vibrations purr second. They appear to be able to generate the purr from either nerves or blood vessels in their voice box.
Communication
Many vets believe purring is definitely a communication tool for cats and is tied to their emotions to signal different moods, desires and needs. Socially, a cat may purr to signal to other animals that they are not a threat. Some believe that a cat's purr is a sign of friendship or a sign of anxiety. Also, purring may be associated with hunger, if a cat starts to purr, maybe the owner will come to investigate the reason for the purring which usually leads to the owner feeding the cat.
Healing Power
There is scientific evidence that the frequency ranges in a cat's purr can stimulate bone growth and healing. Vets feel that a cat will purr to extend their life by lowering levels of heart and bone problems. Other theorists believe the purring may release a pain reliever in the brain called endogenous morphine (aka endorphins). Endorphins resemble the opiates in their abilities to produce analgesia and a feeling of well-being. Also, some say that purring is like that of a cat's mantra of self-healing, vibrating, relaxing sound.
Human Comfort
Some scientists believe that a cat's purr has a therapeutic effect on their owners and can be a healing method for humans. There is evidence that cat owners have lower blood pressure than those who don't own a cat. Many times a cat will lie and arrange themselves on their owner's body over a painful area and the heat and vibration from purring will relieve their owner's pain. Many retirement communities approve cats as a healing animal.
My Conclusion
My observations appear to be somewhat aligned with the scientific and veterinarian community on the reasons why cats purr. I suggest you do your own investigation and observations with your cats and hopefully you'll find the answer to the question, "why do cats purr?"
