Cats knead with their paws to mark their territory and to show affection. The behavior is thought to be a remnant of kittenhood, when kittens knead their mother's belly to stimulate milk production. Kneading is also a sign of contentment and relaxation, as cats often purr while they knead. Kneading can also be a sign of stress or anxiety, and cats may knead when they are feeling overwhelmed.