What some examples of animal imagery in Fahrenheit 451?

In the opening paragraph, the burning book pages are compared to birds trying to fly away. When Millie attempts suicide, Montag compares the tool used to save her to a snake. The Mechanical Hound is a dominant presence throughout the novel. The image of the salamander is dominant as well, as a symbol of the fireman. In addition, the story of the Pheonix plays a prominent role.

This animal imagery expresses the importance of nature in life. The lack of nature, or the manipulation of nature (i.e. the development of the Mechanical Hound), causes death and destruction. The only time animal imagery is positive in the entire novel is when Montag gets out of the river and encounters a deer. At first he thinks it is a Hound, but then realizes his mistake. The deer is peaceful, beautiful, and an expression of nature. This image welcomes Montag into his new life.