No cat can both purr and roar. Sleepy kitty, happy kitty, purr purr purr. They continued to alternate between purr and hiss and fighting one another until one triumphed. Many cats purr while kneading, usually taken to indicate contentment and affection. They may occur as mimesis of a cat's purr. It has also been shown that cats purr to manage pain and soothe themselves. Domestic kittens can purr as early as two days of age. His purr is disproportionately loud for an animal of his size. The mechanism of how cats purr is elusive. It was once believed that only the cats of the genus "Felis" could purr. Females emit a "purr" while brooding. The mechanism by which cats purr is elusive. The cubs might purr as the mother licks them clean after the meal. Females also emit a "purr" while incubating. Jackson delivers the chorus in a reassuring manner; described as a "sotto voce purr".