Imagination
Imagination is the central theme in If I Ran the Zoo. From the outset of the story, Gerald uses his youthful creativity to entertain himself by imagining what would comprise a truly fascinating zoo. Bored with the dull lion exhibit at the real zoo, Gerald uses his mind to invent fanciful creatures such as a ten-footed lion, an elephant-cat hybrid, and a breed of deer with twisted antlers it can't tell apart from those of its family. Ultimately, Gerald's imagination allows him to escape the dullness of everyday life and stimulate his active mind with fantasy.
Public Recognition
Aside from unbelievable creatures, Gerald imagines the public recognition he would receive for developing the McGrew Zoo. The theme of public recognition arises several times throughout the story, suggesting that Gerald wishes to be admired for his theoretical brilliance as a zookeeper. The prevalence of the theme highlights the contrast between Gerald's childish ambition and the adult zookeeper's humble contentment at running an ordinary zoo that operates within the bounds of reality.
Global Conquest
Global conquest is another of the book's major themes. This more controversial theme is expressed through Gerald's belief that he could travel to real and invented countries around the world and simply take the animals he wishes to display. In his imagination, Gerald expects the human inhabitants of the countries he visits to dutifully follow his command as they help him capture their native animals. Gerald's conquest mindset leads him casually to mention bringing back humans as well, such as the chieftain from the Desert of Zind. Gerald's patronizing attitude to the people he believes would help him fill his zoo is also evident in lines such as "And eight Persian Princes will carry the basket, but what their names are, I don't know. So don't ask it." Ultimately, Seuss's perhaps unconscious inclusion of this colonialist theme precipitated enough criticism of the book for it to be removed from publication in 2021.
