Lennie, is a tactile person, loves to touch everything to get a sense of it. He is mentally challenged and completely unaware of his strength. From one instance to the next, he does not seem to learn that he is potentially destructive and must suffer the ultimate when George feels compelled to kill him to save him, initially from the Law or the men that will hunt him down for killing Curley's wife, but also from himself.
Steinbeck associates Lennie with animals, not only for his love to touch them but to show Lennie's capacity for being unpredictable just like an animal. The analogy with a bear
"the way a bear drags his paws,"
and a "creeping" bear is fitting as it evokes a similar emotion in any person who understands the difference between their "teddy bear" and a "real" bear. Both look the same but one is far more deadly. Lennie represents both!
It is fiiting to feel pity for Lennie who just wants to follow his dream and because, with more support from others, things may have been different. Had it not been George's sole responsibility to manage Lennie's capacity for violence, had others not rejected him, their lives could have been different. Maybe that dream could have been a possibility.