Why do you think water rat doesn't want to think about worldwide? Who all lives there?

Rat prefers to stay near the water because it is his home, but he also enjoys traveling with his friends. Rat, like the other characters ,reinforce the theme of home. The greater world can be dangerous with dangerous animals. While all these characters enjoy trekking out into the world, it is equally important that they can enjoy the stability of home once they return. The theme manifests in different ways for each character. Rat and Badger are more set in their domesticity, and prefer to stay close to home, while Mole and Toad want to see as much of the world as they can. However, Mole and Toad are also glad to have somewhere to call their own. It is no accident that the novel ends with a triumphant return to Toad Hall, since it closes the story by reaffirming the power of home.