The theme of this book is "family love" among creatures living on the earth. It is a picture book with very simple content, but for some reason, after reading it, you will feel a sense of warmth. The basic theme is "family," but if you read it from another point of view, there is a bigger theme hidden in this work. If you read it again carefully, you will understand it. If you read it with this in mind, you may enjoy this picture book.