A quick thought:
As I become more familiar with shaking, I get to know through own experience how it’s one of the ways my system heals and restores itself. It shakes out tension, looses muscles and ligaments, restructures itself at the skeletal level, improves blood flow, and by reducing the tension level in the body allows a deeper relaxation, reduces most symptoms, supports healing and makes more energy available. Although I don’t experience it directly, I also assume it aids the function of the internal organs – through healing connective tissues and improving blood flow.
It’s comforting, feels good, makes me trust and become more familiar with the intelligence of the body, and shifts me into experiencing myself as an animal in a good way.
Other mammals shake out tension in a similar way, especially after stressful events, and I wonder if not cats have figured out an additional and similar way to heal themselves – through purring.
It obviously has a social function. It is most likely as comforting for the cat as it is for us when we experience it indirectly. And it may also have an important healing and restoring function for the cat, in the ways described above and more.
Note: When I use the word shaking, it refers to neurogenic tremors, the spontaneous shaking, trembling and vibration the body engages in when it’s allowed to do so. It’s what happens naturally after stressful events, and – it seems – whenever the body needs to shake something out or restore itself.
The photo is of a good cat friend of mine who knows the benefits of purring.