What does the mouse in the first section of John Steinbeck's Of Mice and Men tell you about Lennie?

Lennie is described as an animal. His arms hang at his sides "the way a bear drags his paws." When he gets to the pool, he drinks like a horse. Lennie is large and simple-minded. He is like an animal. It is fitting that the is so affectionate with smaller animals. Lennie is strikingly strong but he wants nothing more than to live on a farm and care for small, cute animals. 

Lennie claims to...

Lennie is described as an animal. His arms hang at his sides "the way a bear drags his paws." When he gets to the pool, he drinks like a horse. Lennie is large and simple-minded. He is like an animal. It is fitting that the is so affectionate with smaller animals. Lennie is strikingly strong but he wants nothing more than to live on a farm and care for small, cute animals. 

Lennie claims to have found the dead mouse and instead of throwing it out, he wants to keep it in his pocket so that he can keep petting it. George tells Lennie to give up the mouse because it isn't sanitary. Lennie recalls how his Aunt Clara used to give him mice. George reminds him that she stopped giving Lennie mice because he would accidentally kill them. 

At the end of the chapter, they discuss the incident in Weed in which Lennie tried to pet a girl's dress. Lennie says, "Jus’ wanted to feel that girl’s dress—jus’ wanted to pet it like it was a mouse . . ." This tells us that Lennie is loving but destructive. In his simplicity and brute strength, his attempts to be loving have the potential to be destructive. Lennie is drawn to cute, soft things. But he has the tendency to destroy these things. His obsession with the dead mouse in the first chapter foreshadows what will happen with the puppy and Curley's wife.