This image depicts a group of four cartoon mice involved in a singing activity, each holding an open book and appearing to sing notes that are represented by musical note symbols above their heads. From left to right:

1. The first mouse is wearing a cap with a bobble, and its eyes are closed as if enjoying the melody it sings. It holds the songbook with both hands.
2. The second mouse, similar in appearance to the first, also wears a bobble cap and sings with closed eyes, holding the book in the same manner.
3. The third mouse is larger, wearing a hat that has a pompom and a rolled rim. It sings with open zeal, bending its back slightly, suggesting a high note, and holds its book with one hand.
4. The fourth mouse does not wear a hat and also holds the book with both hands, singing with closed eyes.

All mice have simplistic, cute round noses, small ears, and long tails, which adds a playful and cheerful character to the image. The style is minimalistic with bold black outlines, and lack of color enhances the simplicity and cartoonish nature of the drawing.