Of Mice and Men- Lennie

Where George has sharp features and definite lines, Lennie is "shapeless."

Lennie is very childlike and innocent and does not understand the basic ways of life, due to his mental disability

Animalistic imagery denotes physical strength, which Lennie does not know the extent of. The animalistic imagery also allows us to sympathise with him as it shows Lennie's lack of understanding of 'man's world'.