Why does the double bass belong to string family?

The double bass belongs to the string family because it produces sound by the vibration of strings, just like other string instruments such as the violin, viola, and cello. These vibrations are amplified by the body of the instrument, which is usually made of wood and has a hollow interior. The strings of the double bass are typically made of gut or metal, and they are played by plucking them with the fingers or bowing them with a horsehair bow.