The plot of the story is precipitated by arrival of the penguin who Mr. Popper names “Captain Cook.” The bird revels in the sheer joy of living until he becomes depressed due to the absence of other penguins in his environment. Captain Cook, despite the financial expenses associated with his care, is the physical embodiment of Mr. Popper’s dream of exploration of the Poles. The bird represents exuberance, the importance of adherence to the natural order, and the potential for mankind to enjoy and bond with animals without imposing damage upon their environment.

Shortly after Captain Cook’s arrival, Mr. Popper realizes that it is imperative to provide the bird with a cool environment. He decides to use the family’s refrigerator (or “icebox”) to house the animal, and he hires a repairman to bore air holes in the door and attach an interior handle to allow the animal to enter and exit the box without assistance. In doing so, Mr. Popper sacrifices the capacity to store food for his own family. This is a precursor to the more significant costs that will be involved in the care of both