What is the theme in Abel's Island by William Steig?

One of the major themes of this book is civilization. Abel is a rich mouse from a noble family. He lives in the ultimate civilized society as he drinks champagne and eats caviar. He is used to the good life. However, when the flood sweeps him away, he leaves civilized society and lands on the deserted island. On the island, he slowly breaks away from his civilized life. For example, to build things, he starts to gnaw at wood.