Lennie begins demonstrating childlike behaviors when he tries to hide the mouse from George on the walk to the ranch. George asks Lennie what he has in his hand. Lennie responds by telling George that he had just wanted to pet the mouse (the mouse is dead). Lennie tells George that he wanted the dead mouse so he could:
"I could pet it with my thumb while we walked along," said Lennie. (6)
Later Lennie is introduced to Slim his new ranch boss. Slim has had a chance to observe Lennie and knows something is not quite right about him. George tells Slim about Lennie.
"I used to play jokes on him. I had fun with 'im. Used to play jokes on him because he was too dumb to take care of himself." (40)
Lennie is given a pup from Slim that was born a day before which he sneaks back to his bunk. George sees it and orders him to take it back to its moher. Lennie can not understand why he can't keep the puppy with him and pet him.
Lennie is childlike because he love soft thing and he needs George to look after him and he loves mices and rabbits. all he thinks about is how George is going to let him tent the rabbits
One of the first descriptions of Lennie is of him and George walking "in single file down the path, and evenin the open oe stayed behind the otheer." (pg 2) This is a great description because it shows that one of the character (Lennie) is delibeately following the other - like a child.
Lennie's certain behaviors also tells us that he has a mind of the child for example; he carried a dead mouse and liked petting it which shows that he's not fully normal.