Here are some possible reasons why Spiegelman used animals as symbols rather than drawing humans in Maus:
- Using animals allows for an additional layer of abstraction and distance from the real human tragedy of the Holocaust. Drawing actual humans could have felt too direct or graphic.
- Animals lend themselves well to caricature and exaggeration of features. This stylistic choice fits with the graphic novel format.
- Certain animal stereotypes map reasonably well to national/ethnic stereotypes - mice as Jews, cats as Nazis, pigs as Poles, etc. This helps the reader follow who represents what group.
- It creates an additional storytelling device. By using animals, Spiegelman is able to explore themes