Of mice and men chapter 1
Lennie is likened to various animals in chapter 1
He 'lumbers' like a BEAR
He drinks from the pool like a HORSE
He holds on to his mouse like a TERRIER
These are all strong animals and indicate that Lennie is physically very strong, but animal analogies also symbolise his low intelligence.
Lennie's lack of understanding about the situation makes him vulnerable.
George confronts Lennie about the mouse - his instinct is to run away when he feels threatened ('looked wildly ay the brush line as though he contemplated running for his freedom') This links to the image of the rabbits running for cover when George and Lennie arrive