Every Tom and Jerry cartoon used a full live orchestra to play the music for each scene.

From 1940 to 1958, composer Scott Bradley led a studio orchestra of 30 to 50 musicians at MGM studios in California. He wrote original music for every single cartoon short. The music had to be timed to the animation frame rate of 24 frames per second.The orchestra used a technique called Mickey Mousing. This means the music mimics the actions on screen exactly. If Tom tripped, a trombone might make a sliding sound at that exact moment. If Jerry ran, the violins played fast notes to match his feet.To stay in sync, the conductor used a click track. This is a steady beat heard through headphones that acts like a metronome. The musicians often watched the animation on a large screen while they recorded the music. This ensured the timing was accurate down to a fraction of a second.Bradley's scores were famous for being very difficult to play. He mixed classical music with jazz and modern styles. Each six-minute cartoon required several days of practice and recording. This level of detail is why the music feels like a part of the characters themselves.