Invented Creatures (Symbol)
The creatures that Gerald invents symbolize the power of a child's imagination. Finding that a lion is not exotic or novel enough to entertain him, Gerald stretches his imagination beyond the limits of reality to conjure up a ten-footed lion, an elephant-cat hybrid, and a series of birds who roost in each other's plumage until they reach an impossible height. With each newly invented animal, Seuss builds on the symbolic significance of children's inherent creativity and capacity to imagine.
The Zookeeper (Symbol)
The zookeeper Gerald watches standing contentedly at the beginning and end of the book is a symbol for adult complacency. While Gerald acknowledges that the man runs a "pretty good" zoo and that the zookeeper seems proud, Gerald is frustrated by the complacency that allows the man to accept his zoo as it is. In reaction to that realistic complacency of the adult zookeeper, Gerald proceeds to imagine how he would change things if he ran his own fantastical zoo.
