Cats purr to show contentment and happiness.

When cats feel safe, comfortable, and relaxed—like when they are resting on their owner's lap or being gently petted—they often purr. This is their way of saying they are happy and at ease. Purring in these moments is a kind of ‘happy sound’ that cats use to communicate their positive feelings to other cats or humans. Even wild cats like lions and cheetahs purr when they feel content.