Why did the author show the mice and the rats together in a panel for example Anja and Vladek are shown as mice in the book are shown as mice are hiding at a place which has rats

Spiegelman chose to write Maus as an animal allegory, His use of mice to portray the Jewish chararcters in the story is based on stereotypical traits, which are anti-Semetic in origin..... namely those of vermin.