In the book of mice and menwhy does steinbeck describe lennie with animal imegery

Steinbeck often compares Lennie to animals because in the first page, Steinbeck writes, "he walked heavily, dragging his feet a little, the way a bear drags his paws." ... It is an important comparison because Lennie seems to be very slow and innocent, but does have the ability to be dangerous like a bear. To be more specific, Lennie has a serious mental disability and seems like he is slow and innocent but in reality he is very dangerous.