First, students fill out a chart that contains examples from the text that portray Lennie as an animal; they must identify the imagery provided and explain the effect/connotation the imagery produces.
Next, students are given a chart with five "types" of people listed. Students create animal imagery for those people in order to show primary characteristics for each one. My students really have fun with this; I have them work in teams and then share their creations with the whole class. That gives us an opportunity to discuss and analyze the images created.