The common household pet known for its ability to purr is the domestic cat. Cats often purr when they are content, which is a soothing sound that can also indicate comfort or self-soothing during stress or pain. The purring sound is produced by the rapid contraction and relaxation of the muscles within their larynx as they breathe. Cats are highly popular pets due to their independent nature and playful behavior, making them beloved companions for many people around the world.