Many composers were (and are) fascinated by cats and some have made music in honour of them.
Here are some examples:
IN OPERA:
Cat duet
From the Opera: "The Child and the Spells" (L'enfant et les sortilèges) by Maurice Ravel
(Angelica have sung the white cat at the Norwegian National Opera, the operacats did some of the coaching ;)
IN MUSICALS
An obvious find: "Cats" by Andrew Lloyd Webber
CLASSICAL MUSIC
Humorous duet for two cats
Attributed: Rossini/ Compilated by: de Pearsall
CARTOONS
Evil Siamese in "Lady and the Tramp"
"The Aristocats" practise their arpeggios and scales
Tom is a famous baritone and sings Figaro's aria from Rossini's "The Barber of Seville", Jerry tries to sleep.