Because Motor purrs almost all the time, I wanted to know how he does that. I have always heard that cats purr when they are happy or content. It is good to know he is happy in his new home.
"It turns out that cats have special wiring! The wiring travels from the brain to the muscles in the voice box, and this wiring is able to vibrate the muscles so that they act as a valve for air flowing past the voice box. The muscles work both during inhalation and exhalation, which creates the impression that cats can purr continuously. The air passes through the valve, which opens and closes rapidly to create the purring sound." (from How Stuff Works)