It's difficult to create a thesis statement without first choosing a topic. Once you choose a topic, thing about something about that topic that you'd like to prove. For example, Night has several examples in which the Jews are put in such terrible situations that they begin to act like animals, forgetting their own families in order to survive. Your thesis statement could be something like this: When placed in extreme survival situations, Eli and other Jews in his situation behave in animalistic ways. Please, do not copy it blindly. Intstead, you may just check what the guys from Prime Writing site.